leetcode-每日一题-3025. 人员站位的方案数 I-C语言

• 输入：
  2 <= n <= 50
  points[i].length == 2
  0 <= points[i][0], points[i][1] <= 50
  points[i] 点对两两不同。

// 按x降序，按y升序
int cmp(const void *a, const void *b) {
    int *p = *(int **)a;
    int *q = *(int **)b;
    if(p[0] == q[0]){
        return p[1]-q[1];
    } 
    else return q[0]-p[0];
}
// 判断c点是否在a为右下角，b为左上角的矩形和边界内
bool IsPad(int *pointa, int *pointb, int *pointc) {
    return !(pointc[0] > pointa[0] || pointc[0] < pointb[0] || pointc[1] < pointa[1] || pointc[1] > pointb[1]);
}
int numberOfPairs(int** points, int pointsSize, int* pointsColSize) {
    int res = 0;
    qsort(points, pointsSize, sizeof(int *), cmp);
    for(int i=0; i<pointsSize; i++) {
        for(int j=i+1; j<pointsSize; j++) {
            if(points[j][1] < points[i][1]){
                continue;
            }
            int k=i+1;
            while(k<j) {
                if(IsPad(points[i], points[j], points[k])) break;
                k++;
            }
            if(k == j) res++;
        }
    }
    return res;
}