poj 1818

#include <cstdio>
#include <iostream>
#include <iomanip>
#include <string>
#include <cstdlib>
#include <cstring>
#include <queue>
#include <set>
#include <vector>
#include <map>
#include <algorithm>
#include <cmath>
#include <stack>

#define INF 0x3f3f3f3f
#define IMAX 2147483646;
#define LINF 0x3f3f3f3f3f3f3f3f
#define ll long long
#define ull unsigned long long
#define uint unsigned int

using namespace::std;

int n, x, k, qq[5010], add;
int vis[5010];

int c(int now){
    memset(vis, 0, sizeof(vis));
	vis[now] = 1;
    add = 0; qq[add++] = now;
    for (int kase = 1; kase <= x; kase++) {
        int t = add;
        for (int i = 0; i < t; i++) 
            for (int j = max(1, qq[i] - k); j <= n; j++)
                if (vis[j] == 0) {
					vis[j] = 1;
					qq[add++] = j;
					break;
                }
    }
    for (int i = 1; i <= n; i++)
        if (vis[i] == 0) return 0;
    return 1;
}

int main () {
	scanf("%d %d", &n, &k); x = 0;
    for (int i = 1; i < n; x++, i *= 2);

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