#1,3,4 TLE #2,5,6 RE 求助

Zhaozimo1207 @ 2024-03-30 23:55:41

#include <bits/stdc++.h>
#define ll long long
using namespace std;
ll n,m,a[100005];
int find(int x){
    int left = 1,right = n;
    int middle = (left + right) / 2;
    while(left < right){
        if(a[middle] == x) return middle;
        else if(x < a[middle]) middle = right;
        else middle = left + 1;
    } 
    return -1;
}
int main(){
    cin >> n >> m;
    for(int i = 1;i <= n;i ++){
        cin >> a[i]; 
    }
    for(int i = 1;i <= m;i ++){
        int x;
        cin >> x;
        cout << find(x) << " ";
    }
    return 0;
}

by Zhaozimo1207 @ 2024-03-30 23:57:21

可否帮我改一下代码，谢谢

by Forgotten_0114507666 @ 2024-03-31 00:34:03

@Zhaozimo1207

问题：

0. 快读呢？
1. find 一点没对，全程left和right没改，只查找了随机一个 x 的下标。

改完的：

#include<cstdio>
#include<cctype>
#define forr(i,a,b) for(int i=(a);i<=(b);i++)
#define roff(i,a,b) for(int i=(a);i>=(b);i--)
typedef long long ll;
inline ll max(ll a,ll b){return a>b?a:b;}
inline ll min(ll a,ll b){return a<b?a:b;}
inline void gmax(ll&a,ll b){if(a<b)a=b;}
inline void gmin(ll&a,ll b){if(a>b)a=b;}
inline ll abs(ll x){return x>0?x:-x;}
inline ll mod(ll x,ll m){return (x%m+m)%m;}
inline ll swap(ll&a,ll&b){a^=b^=a^=b;}
inline ll powm(ll x,ll p,ll m){
    ll ret=1;
    while(p){
        if(p&1)ret=mod(ret*x,m);
        x=mod(x*x,m);p>>=1;
    }
    return ret;
}
inline ll gcd(ll a,ll b){
    if(b==0)return a;
    return gcd(b,a%b);
}
ll qr(){
    ll ans=0;int ch=getchar();bool sgn=false;
    while(!isdigit(ch)){if(ch=='-')sgn=true;ch=getchar();}
    while(isdigit(ch)){ans=(ans<<3)+(ans<<1)+(ch^'0');ch=getchar();}
    return sgn?-ans:ans;
}
void qw(ll d,const char* append="",bool firstch=true){
    if(firstch){
        if(!d)putchar('0');
        if(d<0)putchar('-'),d=-d;
    }
    if(d){
        qw(d/10,"",false);
        putchar(d%10 + '0');
    }
    if(firstch)fputs(append,stdout);
}
ll n,m,a[100005];
int find(int x){
    int left = 1,right = n;
    int middle;
    while(left < right){
        middle = (left + right ) / 2;
        if(x <= a[middle]) right = middle;
        else left = middle + 1;
    }
    if(a[left] == x)return left;
    return -1;
}
int main(){
    n=qr();m=qr();
    for(int i = 1;i <= n;i ++){
        a[i]=qr(); 
    }
    for(int i = 1;i <= m;i ++){
        qw(find(qr()),"\n");
    }
    return 0;
}

by Zhaozimo1207 @ 2024-03-31 08:56:30

@Forgotten_0x1328FB6

感谢，编程小白，已AC