CodeForces 1490G :Old Floppy Drive 二分

传送门

题目描述

圆盘上有 n 个数,起初指针在第一个位置,m 次询问,每次询问回答指针至少移动多少次使得指针所经过的所有数的和 >= x(指针不可反向)

分析

我们假设,最后退出的位置为x,那么x一定在这一圈前缀和最大处或者最大处之前,那么我们减去一圈前缀和最大值,剩下的部分就只能用一整圈的和来弥补,除以一整圈的和,向上取整,最后二分前缀和最大值即可

代码

#pragma GCC optimize(3)
#include <bits/stdc++.h>
#define debug(x) cout<<#x<<":"<<x<<endl;
#define dl(x) printf("%lld\n",x);
#define di(x) printf("%d\n",x);
#define _CRT_SECURE_NO_WARNINGS
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> PII;
typedef vector<int> VI;
const int INF = 0x3f3f3f3f;
const int N = 2e5 + 10;
const ll mod= 1000000007;
const double eps = 1e-9;
const double PI = acos(-1);
template<typename T>inline void read(T &a){
    
    char c=getchar();T x=0,f=1;while(!isdigit(c)){
    
    if(c=='-')f=-1;c=getchar();}
while(isdigit(c)){
    
    x=(x<<1)+(x<<3)+c-'0';c=getchar();}a=f*x;}
int gcd(int a,int b){
    
    return (b>0)?gcd(b,a%b):a;}
ll a[N],n,m;


int main(){
    
    
    int T;
    read(T);
    while(T--){
    
    
        read(n),read(m);
        ll s = 0;
        for(int i = 1;i <= n;i++){
    
    
            ll d;
            read(d);
            s += d;
            a[i] = max(a[i - 1],s);
        }
        while(m--){
    
    
            ll q;
            read(q);
            if(q <= a[n]){
    
    
                printf("%d ",(lower_bound(a + 1,a + 1 + n,q) - a - 1));
            }
            else{
    
    
                if(s <= 0){
    
    
                    printf("-1 ");
                }
                else{
    
    
                    ll d = q - a[n];
                    ll t = (d + s - 1) / s;
                    q -= t * s;
                    ll res;
                    res = t * n + 1ll * (lower_bound(a + 1,a + 1 + n,q) - a - 1);
                    printf("%lld ",res);
                }
            }
        }
        puts("");
    }
}

/**
*  ┏┓   ┏┓+ +
* ┏┛┻━━━┛┻┓ + +
* ┃       ┃
* ┃   ━   ┃ ++ + + +
*  ████━████+
*  ◥██◤ ◥██◤ +
* ┃   ┻   ┃
* ┃       ┃ + +
* ┗━┓   ┏━┛
*   ┃   ┃ + + + +Code is far away from  
*   ┃   ┃ + bug with the animal protecting
*   ┃    ┗━━━┓ 神兽保佑,代码无bug 
*   ┃        ┣┓
*    ┃        ┏┛
*     ┗┓┓┏━┳┓┏┛ + + + +
*    ┃┫┫ ┃┫┫
*    ┗┻┛ ┗┻┛+ + + +
*/


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转载自blog.csdn.net/tlyzxc/article/details/113872146
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