feat: add ts solution to lc problem: No.0640

No.0640.Solve the Equation

Author: YangFong

solution/0600-0699/0640.Solve the Equation/README.md

@@ -192,6 +192,66 @@ func solveEquation(equation string) string {
 }
 ```
 
+### **TypeScript**
+
+```ts
+function solveEquation(equation: string): string {
+    const [left, right] = equation.split('=');
+    const createExpr = (s: string) => {
+        let x = 0;
+        let n = 0;
+        let i = 0;
+        let sym = 1;
+        let cur = 0;
+        let isX = false;
+        for (const c of s) {
+            if (c === '+' || c === '-') {
+                if (isX) {
+                    if (i === 0 && cur === 0) {
+                        cur = 1;
+                    }
+                    x += cur * sym;
+                } else {
+                    n += cur * sym;
+                }
+                isX = false;
+                cur = 0;
+                i = 0;
+                if (c === '+') {
+                    sym = 1;
+                } else {
+                    sym = -1;
+                }
+            } else if (c === 'x') {
+                isX = true;
+            } else {
+                i++;
+                cur *= 10;
+                cur += Number(c);
+            }
+        }
+        if (isX) {
+            if (i === 0 && cur === 0) {
+                cur = 1;
+            }
+            x += cur * sym;
+        } else {
+            n += cur * sym;
+        }
+        return [x, n];
+    };
+    const lExpr = createExpr(left);
+    const rExpr = createExpr(right);
+    if (lExpr[0] === rExpr[0]) {
+        if (lExpr[1] !== rExpr[1]) {
+            return 'No solution';
+        }
+        return 'Infinite solutions';
+    }
+    return `x=${(lExpr[1] - rExpr[1]) / (rExpr[0] - lExpr[0])}`;
+}
+```
+
 ### **...**
 
 ```

solution/0600-0699/0640.Solve the Equation/README_EN.md

@@ -167,6 +167,66 @@ func solveEquation(equation string) string {
 }
 ```
 
+### **TypeScript**
+
+```ts
+function solveEquation(equation: string): string {
+    const [left, right] = equation.split('=');
+    const createExpr = (s: string) => {
+        let x = 0;
+        let n = 0;
+        let i = 0;
+        let sym = 1;
+        let cur = 0;
+        let isX = false;
+        for (const c of s) {
+            if (c === '+' || c === '-') {
+                if (isX) {
+                    if (i === 0 && cur === 0) {
+                        cur = 1;
+                    }
+                    x += cur * sym;
+                } else {
+                    n += cur * sym;
+                }
+                isX = false;
+                cur = 0;
+                i = 0;
+                if (c === '+') {
+                    sym = 1;
+                } else {
+                    sym = -1;
+                }
+            } else if (c === 'x') {
+                isX = true;
+            } else {
+                i++;
+                cur *= 10;
+                cur += Number(c);
+            }
+        }
+        if (isX) {
+            if (i === 0 && cur === 0) {
+                cur = 1;
+            }
+            x += cur * sym;
+        } else {
+            n += cur * sym;
+        }
+        return [x, n];
+    };
+    const lExpr = createExpr(left);
+    const rExpr = createExpr(right);
+    if (lExpr[0] === rExpr[0]) {
+        if (lExpr[1] !== rExpr[1]) {
+            return 'No solution';
+        }
+        return 'Infinite solutions';
+    }
+    return `x=${(lExpr[1] - rExpr[1]) / (rExpr[0] - lExpr[0])}`;
+}
+```
+
 ### **...**
 
 ```

solution/0600-0699/0640.Solve the Equation/Solution.ts

@@ -0,0 +1,55 @@
+function solveEquation(equation: string): string {
+    const [left, right] = equation.split('=');
+    const createExpr = (s: string) => {
+        let x = 0;
+        let n = 0;
+        let i = 0;
+        let sym = 1;
+        let cur = 0;
+        let isX = false;
+        for (const c of s) {
+            if (c === '+' || c === '-') {
+                if (isX) {
+                    if (i === 0 && cur === 0) {
+                        cur = 1;
+                    }
+                    x += cur * sym;
+                } else {
+                    n += cur * sym;
+                }
+                isX = false;
+                cur = 0;
+                i = 0;
+                if (c === '+') {
+                    sym = 1;
+                } else {
+                    sym = -1;
+                }
+            } else if (c === 'x') {
+                isX = true;
+            } else {
+                i++;
+                cur *= 10;
+                cur += Number(c);
+            }
+        }
+        if (isX) {
+            if (i === 0 && cur === 0) {
+                cur = 1;
+            }
+            x += cur * sym;
+        } else {
+            n += cur * sym;
+        }
+        return [x, n];
+    };
+    const lExpr = createExpr(left);
+    const rExpr = createExpr(right);
+    if (lExpr[0] === rExpr[0]) {
+        if (lExpr[1] !== rExpr[1]) {
+            return 'No solution';
+        }
+        return 'Infinite solutions';
+    }
+    return `x=${(lExpr[1] - rExpr[1]) / (rExpr[0] - lExpr[0])}`;
+}