算法训练营第二十一天| 基本计算器 II

1.题目链接：https://leetcode.cn/problems/basic-calculator-ii/description/ 优秀题解：https://leetcode.cn/problems/basic-calculator-ii/solutions/91271/chai-jie-fu-za-wen-ti-shi-xian-yi-ge-wan-zheng-ji-/

2.

#include <stdio.h> #include <stdlib.h> #include <ctype.h> #include <string.h> int calculate(char* s) { int stackSize = 4; int* stack = (int*)malloc(stackSize * sizeof(int)); int top = -1; int num = 0; char op = '+'; int len = strlen(s); for (int i = 0; i < len; i++) { if (isdigit(s[i])) { num = num * 10 + (s[i] - '0'); } if ((!isdigit(s[i]) && s[i] != ' ') || i == len - 1) { if (top + 1 >= stackSize) { stackSize *= 2; stack = (int*)realloc(stack, stackSize * sizeof(int)); } switch (op) { case '+': stack[++top] = num; break; case '-': stack[++top] = -num; break; case '*': stack[top] *= num; break; case '/': stack[top] = stack[top] / num; break; } op = s[i]; num = 0; } } int result = 0; for (int j = 0; j <= top; j++) { result += stack[j]; } free(stack); return result; }