FZU - 2203 單縱大法好（貪心+二分）

兩年前的坑現在補上，經典的貪心+二分

#include <stdio.h>
#include <string.h>
const int maxn = 200005;
int N,K,A,M;
int pos[maxn];
bool vis[maxn];
bool judge(int m)
{
    int i,cnt,len;
    memset( vis,false,sizeof(vis) );
    for(i = 0; i < m; i++)
        vis[pos[i]] = true;
    cnt = 0;
    len = 0;
    for(i = 1; i <= N; i++) {
        if(vis[i]) {
            len = 0;
            continue;
        }
        len++;
        if(len == A) {
            cnt++;
            len = 0;
            i++;
        }
    }
    if(cnt >= K) return 0;
    else return 1;
}
int main(void)
{
    int L,R,mid,ans,i;
    while(scanf("%d %d %d",&N,&K,&A) != EOF) {
        ans = -1;
        scanf("%d",&M);
        for(i = 0; i < M; i++)
            scanf("%d",&pos[i]);
        L = 1,R = M;
        while(L <= R) {
            //printf("%d %d %d\n",L,R,mid);
            mid = (L + R) >> 1;
            if(judge(mid)) {
                ans = mid;
                R = mid - 1;
            }
            else L = mid + 1;
        }
        printf("%d\n",ans);
    }
    return 0;
}