用c++写一个函数用来统计字符串中各字母出现的次数,示例： 输入：X2Y3XZ，输出：X3Y3Z1； 输入：Z3X(XY)2，输出：X3Y2Z3； 输入：Z4(Y2(XZ2)3)2X2，输出：X8Y4Z16；

#include <stdio.h>
#include <string.h>
#define MAX_LEN 1000

void count(char *str, int *cnt) {
    int len = strlen(str);
    for (int i = 0; i < len;) {
        if (str[i] >= 'A' && str[i] <= 'Z') {
            int j = i + 1;
            while (j < len && str[j] >= '0' && str[j] <= '9') {
                j++;
            }
            int num = 0;
            for (int k = i + 1; k < j; k++) {
                num = num * 10 + str[k] - '0';
            }
            cnt[str[i] - 'A'] += num;
            i = j;
        } else if (str[i] == '(') {
            int j = i + 1, cnt2[26] = {0};
            while (str[j] != ')') {
                count(str + j, cnt2);
                int k = j + 1;
                while (k < len && str[k] >= '0' && str[k] <= '9') {
                    k++;
                }
                int num = 0;
                for (int l = j; l < k; l++) {
                    num = num * 10 + str[l] - '0';
                }
                for (int l = 0; l < 26; l++) {
                    cnt[l] += cnt2[l] * num;
                }
                j = k;
            }
            i = j + 1;
        } else {
            i++;
        }
    }
}

int main() {
    char str[MAX_LEN];
    int cnt[26] = {0};
    scanf("%s", str);
    count(str, cnt);
    for (int i = 0; i < 26; i++) {
        if (cnt[i] > 0) {
            printf("%c%d", i + 'A', cnt[i]);
        }
    }
    printf("\n");
    return 0;
}