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feat: add solutions to lc problem: No.0983
No.0983.Minimum Cost For Tickets
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‎solution/0900-0999/0983.Minimum Cost For Tickets/README.md

Lines changed: 149 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -63,22 +63,170 @@
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<!-- 这里可写通用的实现逻辑 -->
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**方法一：记忆化搜索 + 二分查找**
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定义 `dfs(i)` 表示从第 `i` 次出行开始的最低消费。答案为 `dfs(0)`。
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采用记忆化搜索的方法，记录已经计算过的结果，避免重复计算。
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时间复杂度 $O(n)$，空间复杂度 $O(n)$。其中 $n$ 为 `days` 的长度。
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<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def mincostTickets(self, days: List[int], costs: List[int]) -> int:
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@cache
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def dfs(i):
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if i >= len(days):
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return 0
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res = inf
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for c, d in zip(costs, [1, 7, 30]):
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j = bisect_left(days, days[i] + d)
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res = min(res, c + dfs(j))
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return res
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return dfs(0)
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class Solution {
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private static final int[] T = new int[]{1, 7, 30};
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private int[] costs;
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private int[] days;
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private int[] f;
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private int n;
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public int mincostTickets(int[] days, int[] costs) {
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n = days.length;
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f = new int[n];
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this.costs = costs;
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this.days = days;
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Arrays.fill(f, -1);
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return dfs(0);
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}
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private int dfs(int i) {
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if (i >= n) {
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return 0;
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}
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if (f[i] != -1) {
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return f[i];
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}
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int res = Integer.MAX_VALUE;
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for (int k = 0; k < 3; ++k) {
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int j = lowerBound(days, days[i] + T[k]);
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res = Math.min(res, costs[k] + dfs(j));
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}
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f[i] = res;
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return res;
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}
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private int lowerBound(int[] days, int x) {
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int left = 0, right = days.length;
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while (left < right) {
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int mid = (left + right) >> 1;
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if (days[mid] >= x) {
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right = mid;
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} else {
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left = mid + 1;
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}
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}
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return left;
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}
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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vector<int> t = {1, 7, 30};
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vector<int> days;
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vector<int> costs;
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vector<int> f;
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int n;
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int mincostTickets(vector<int>& days, vector<int>& costs) {
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n = days.size();
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this->days = days;
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this->costs = costs;
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f.assign(n, -1);
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return dfs(0);
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}
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int dfs(int i) {
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if (i >= n) return 0;
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if (f[i] != -1) return f[i];
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int res = INT_MAX;
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for (int k = 0; k < 3; ++k) {
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int j = lower_bound(days.begin(), days.end(), days[i] + t[k]) - days.begin();
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res = min(res, costs[k] + dfs(j));
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}
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f[i] = res;
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return res;
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}
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};
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```
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### **Go**
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```go
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func mincostTickets(days []int, costs []int) int {
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t := []int{1, 7, 30}
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n := len(days)
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f := make([]int, n)
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for i := range f {
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f[i] = -1
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}
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var dfs func(i int) int
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dfs = func(i int) int {
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if i >= n {
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return 0
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}
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if f[i] != -1 {
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return f[i]
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}
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res := 0x3f3f3f3f
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for k, c := range costs {
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j := lowerBound(days, days[i]+t[k])
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res = min(res, c+dfs(j))
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}
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f[i] = res
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return res
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}
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return dfs(0)
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}
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func lowerBound(arr []int, x int) int {
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left, right := 0, len(arr)
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for left < right {
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mid := (left + right) >> 1
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if arr[mid] >= x {
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right = mid
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} else {
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left = mid + 1
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}
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}
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return left
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}
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func min(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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```
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### **TypeScript**

‎solution/0900-0999/0983.Minimum Cost For Tickets/README_EN.md

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Original file line numberDiff line numberDiff line change
@@ -64,13 +64,153 @@ In total, you spent $17 and covered all the days of your travel.
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### **Python3**
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```python
67-
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class Solution:
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def mincostTickets(self, days: List[int], costs: List[int]) -> int:
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@cache
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def dfs(i):
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if i >= len(days):
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return 0
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res = inf
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for c, d in zip(costs, [1, 7, 30]):
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j = bisect_left(days, days[i] + d)
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res = min(res, c + dfs(j))
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return res
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return dfs(0)
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```
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### **Java**
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```java
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class Solution {
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private static final int[] T = new int[]{1, 7, 30};
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private int[] costs;
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private int[] days;
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private int[] f;
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private int n;
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public int mincostTickets(int[] days, int[] costs) {
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n = days.length;
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f = new int[n];
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this.costs = costs;
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this.days = days;
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Arrays.fill(f, -1);
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return dfs(0);
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}
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private int dfs(int i) {
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if (i >= n) {
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return 0;
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}
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if (f[i] != -1) {
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return f[i];
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}
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int res = Integer.MAX_VALUE;
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for (int k = 0; k < 3; ++k) {
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int j = lowerBound(days, days[i] + T[k]);
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res = Math.min(res, costs[k] + dfs(j));
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}
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f[i] = res;
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return res;
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}
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private int lowerBound(int[] days, int x) {
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int left = 0, right = days.length;
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while (left < right) {
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int mid = (left + right) >> 1;
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if (days[mid] >= x) {
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right = mid;
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} else {
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left = mid + 1;
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}
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}
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return left;
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}
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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vector<int> t = {1, 7, 30};
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vector<int> days;
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vector<int> costs;
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vector<int> f;
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int n;
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int mincostTickets(vector<int>& days, vector<int>& costs) {
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n = days.size();
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this->days = days;
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this->costs = costs;
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f.assign(n, -1);
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return dfs(0);
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}
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int dfs(int i) {
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if (i >= n) return 0;
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if (f[i] != -1) return f[i];
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int res = INT_MAX;
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for (int k = 0; k < 3; ++k) {
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int j = lower_bound(days.begin(), days.end(), days[i] + t[k]) - days.begin();
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res = min(res, costs[k] + dfs(j));
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}
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f[i] = res;
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return res;
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}
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};
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```
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### **Go**
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```go
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func mincostTickets(days []int, costs []int) int {
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t := []int{1, 7, 30}
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n := len(days)
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f := make([]int, n)
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for i := range f {
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f[i] = -1
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}
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var dfs func(i int) int
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dfs = func(i int) int {
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if i >= n {
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return 0
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}
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if f[i] != -1 {
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return f[i]
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}
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res := 0x3f3f3f3f
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for k, c := range costs {
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j := lowerBound(days, days[i]+t[k])
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res = min(res, c+dfs(j))
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}
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f[i] = res
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return res
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}
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return dfs(0)
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}
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func lowerBound(arr []int, x int) int {
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left, right := 0, len(arr)
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for left < right {
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mid := (left + right) >> 1
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if arr[mid] >= x {
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right = mid
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} else {
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left = mid + 1
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}
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}
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return left
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}
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func min(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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```
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### **TypeScript**

‎solution/0900-0999/0983.Minimum Cost For Tickets/Solution.cpp

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,28 @@
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class Solution {
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public:
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vector<int> t = {1, 7, 30};
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vector<int> days;
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vector<int> costs;
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vector<int> f;
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int n;
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int mincostTickets(vector<int>& days, vector<int>& costs) {
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n = days.size();
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this->days = days;
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this->costs = costs;
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f.assign(n, -1);
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return dfs(0);
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}
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int dfs(int i) {
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if (i >= n) return 0;
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if (f[i] != -1) return f[i];
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int res = INT_MAX;
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for (int k = 0; k < 3; ++k) {
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int j = lower_bound(days.begin(), days.end(), days[i] + t[k]) - days.begin();
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res = min(res, costs[k] + dfs(j));
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}
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f[i] = res;
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return res;
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}
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};

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