滑动窗口？

别人的总结帖 https://leetcode-cn.com/problems/corporate-flight-bookings/solution/xi-fa-dai-ni-xue-suan-fa-yi-ci-gao-ding-qian-zhu-5/

leetcode题目：https://leetcode-cn.com/problems/corporate-flight-bookings/submissions/

/**
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* corpFlightBookings(int** bookings, int bookingsSize, int* bookingsColSize, int n, int* returnSize){

    int *returnArr = (int *)malloc(sizeof(int) * n);
    int i, j, k;
    for (i = 0; i < n; i++) {
        returnArr[i] = 0;
    }
    // 第 i 站上来了 k 个人， 一直到 第 j 站都在飞机上，到第 j + 1 就不在飞机上了
    // 用前缀优化，1,2,10，那么3设成-10，ret[i] += ret[i-1]；
    /*
        1   2   3     4    5
        10      -10            (由于后面的4,5都是基于3，相当于都-10了)
            20       -20
            25

        10  10+20+25  55-10   45-20  25
    */ 
    

    int tmp_i, tmp_j;

    for (j = 0; j < bookingsSize; j++) {
        tmp_i = bookings[j][0];
        tmp_j = bookings[j][1];
        returnArr[tmp_i - 1] += bookings[j][2];
        if (tmp_j < n) {
            returnArr[tmp_j] -= bookings[j][2];
        }
        
    }

    for (i = 1; i < n; i++) {
        returnArr[i] += returnArr[i - 1];
    }

    *returnSize = n;
    return returnArr;

}