NOIP2012-------跳石头（C语言）

#include<stdio.h>
long a[50035];

int check(long mid, long n, long m) {
    long last, i, ans;
    last = a[0];
    ans = 0;
    for (i = 1; i <= (n+1); i++) {
        if (a[i] - last < mid) {
            ans++;
        }
        else {
            last = a[i];
        }
    }
    if (ans > m) {
        return 0;
    }
    return 1;
}

int main() {
    long l, n, m;
    scanf("%ld %ld %ld", &l, &n, &m);
    a[0] = 0;
    a[n + 1] = l;
    int i;
    for (i = 1; i <= n; i++) {
        scanf("%ld", &a[i]);
    }
    long left, right;
    left = 0;
    right = l;
    long mid;
    while (left <= right) {
        mid = (left + right) >> 1;
        if (check(mid, n, m)) {
            left = mid+1;
        }
        else {
            right = mid-1;
        }
        
    }
    printf("%ld", left-1);
    return 0;
}