【leetcode】增减字符串匹配

int* diStringMatch(char * S, int* returnSize){
    int i, j, len = strlen(S), minVal = 0, maxVal = len;
    int* arr = (int*)calloc(len + 1, sizeof(int));
    for (i = 0; i < len; i++)
        arr[i] = (S[i] == 'I') ? minVal++ : maxVal--;
    arr[len] = minVal;
    *returnSize = len + 1;
    return arr;
}