C++经典算法题-最大访客数

#include <stdio.h>
#include <stdlib.h> 
#define MAX 100
#define SWAP(x,y) {int t; t = x; x = y; y = t;}

    int partition(int[], int, int);
    void quicksort(int[], int, int); // 快速排序法
    int maxguest(int[], int[], int, int);

    int main(void) {
        int x[MAX] = {0};
        int y[MAX] = {0};
        int time = 0; int count = 0;

        printf("\n输入来访与离开125;时间(0~24)："); printf("\n范例：10 15");
        printf("\n输入-1 -1结束"); while(count < MAX) {

            printf("\n>>");
            scanf("%d %d", &x[count], &y[count]); if(x[count] < 0)
                break; count++;
        }

        if(count >= MAX) {
            printf("\n超出最大访客数(%d)", MAX); count--;
        }

        //  预先排序
        quicksort(x, 0, count);
        quicksort(y, 0, count);

        while(time < 25) {
            printf("\n%d 时的最大访客数：%d",
                    time, maxguest(x, y, count, time));
            time++;
        }

        printf("\n");

        return 0;
    }

    int maxguest(int x[], int y[], int count, int time) { int i, num = 0;

        for(i = 0; i <= count; i++) { if(time > x[i])
            num++; if(time > y[i])
            num--;
        }

        return num;
    }

    int partition(int number[], int left, int right) {

        int i, j, s;

        s = number[right]; i = left - 1;

        for(j = left; j < right; j++) { if(number[j] <= s) {
            i++;
            SWAP(number[i], number[j]);
        }
        }

        SWAP(number[i+1], number[right]); return i+1;
    }

    void quicksort(int number[], int left, int right) { int q;

        if(left < right) {
            q = partition(number, left, right); quicksort(number, left, q-1); quicksort(number, q+1, right);
        }
    }