hdu 4004 二分查找

直接二分查找答案即可，我的判断函数没有像大牛们那样优化，但是过是没问题的~

/*
 * hdu4004/linux.cpp
 * Created on: 2011-9-4
 * Author    : ben
 */
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;

const int MAXN = 500010;
int stone[MAXN], L, N, M;

int step(int dis) {
    int ret, cur, next;
    next = ret = cur = 0;
    while (cur <= N) {
        next = cur + 1;
        while (next <= N + 1 && stone[next] - stone[cur] <= dis) {
            next++;
        }
        if (cur == next - 1) {
            return 0x7fffffff;
        }
        cur = next - 1;
        ret++;
    }
    return ret;
}

void work();
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    work();
    return 0;
}

void work() {
    int mid, high, low, ans;
    while (scanf("%d%d%d", &L, &N, &M) == 3) {
        stone[0] = 0;
        for (int i = 1; i <= N; i++) {
            scanf("%d", &stone[i]);
        }
        stone[N + 1] = L;
        sort(stone, stone + N + 2);
        low = 0;
        high = L;
        while (low <= high) {
            mid = (low + high) / 2;
            if (step(mid) > M) {
                low = mid + 1;
            } else {
                high = mid - 1;
                ans = mid;
            }
        }
        printf("%d\n", ans);
    }
}