HDU 4004 The Frog's Games 二分 贪心

戳这里：HDU 4004

//思路：二分经典入门题...贪心判方案是否可行

#include "bits/stdc++.h"
using namespace std;
int L, n, m;
int pos[500010], dis[500010];

bool Cant(int Dis_Jump)
{
    int i, Dis_Sum = 0, Count = 0;
    for(i = 1; i <= n + 1; ++i) {
        if(dis[i] > Dis_Jump) {
            return 1;
        }
        Dis_Sum += dis[i];
        if(Dis_Sum > Dis_Jump) {
            ++Count;
            Dis_Sum = dis[i];
        }
    }
    ++Count;
    if(Count > m)
        return 1;
    return 0;
}

int main()
{
    while(scanf("%d%d%d", &L, &n, &m) != EOF) {
        int i;
        for(i = 1; i <= n; ++i) {
            scanf("%d", &pos[i]);
        }
        sort(pos + 1, pos + 1 + n);
        for(i = 1; i <= n; ++i) {
            dis[i] = pos[i] - pos[i - 1];
        }
        dis[i] = L - pos[i - 1];
//        for(i = 1; i <= n + 1; ++i) {
//            printf(" ee i == %d dis == %d
", i, dis[i]);
//        }

        int l = 0, r = L, mid;
        while(l <= r) {
            mid = (l + r) >> 1;
            if(Cant(mid)) {
                l = mid + 1;
            }
            else {
                r = mid - 1;
            }
        }
        printf("%d
", l);
    }
}