hihoCoder #1269 : 优化延迟 【二分 + 优先队列】

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>
#define PI acos(-1.0)
#define CLR(a, b) memset(a, (b), sizeof(a))
#define fi first
#define se second
using namespace std;
typedef long long LL;
typedef pair<int, int> pii;
const int MAXN = 1e5+10;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
void getmax(int &a, int b) {a = max(a, b); }
void getmin(int &a, int b) {a = min(a, b); }
void add(LL &x, LL y) { x += y; x %= MOD; }
priority_queue<int, vector<int>, less<int> > Q;
int N; LL S;
int a[MAXN];
LL Count(int o)
{
LL ans = 0;
int i = 1, j = 1;
while(i <= N)
{
while(Q.size() < o && i <= N) {
Q.push(a[i]), i++;
}
int v = Q.top(); Q.pop();
ans += 1LL * v * j; j++;
}
while(!Q.empty())
{
int v = Q.top(); Q.pop();
ans += 1LL * v * j; j++;
}
return ans;
}
int main()
{
while(scanf("%d%lld", &N, &S) != EOF)
{
for(int i = 1; i <= N; i++) scanf("%d", &a[i]);
int l = 1, r = N;
int ans = -1;
while(r >= l)
{
int mid = (l + r) >> 1;
if(Count(mid) <= S)
{
ans = mid;
r = mid-1;
}
else
l = mid+1;
}
cout << ans << endl;
}
return 0;
}