Atcoder Beginner Contest 308

news2024/11/16 5:25:00

A - New Scheme

AC代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#define int long long
using namespace std;
const int N = 110;
int a[N];
void solve()
{
    for (int i = 0; i < 8; i++) cin >> a[i];
    if (a[0] < 100 || a[0]>675 || a[0] % 25 != 0) {
        puts("No");
        return;
    }
    for (int i = 1; i < 8; i++) {
        if (a[i] < a[i - 1]|| a[i] < 100 || a[i]>675 || a[i] % 25 != 0) {
            puts("No");
            return;
        }
    }
    puts("Yes");
}
signed main()
{
    solve();
    return 0;
}

B - Default Price

AC代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#include<map>
#define int long long
using namespace std;
const int N = 110;
string c[N],d[N];
int p[N];
map<string, int>mp;
int res;
void solve()
{
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> c[i];
    for (int i = 1; i <= m; i++) cin >> d[i];
    for (int i = 0; i <= m; i++) cin >> p[i];
    for (int i = 1; i <= m; i++) mp[d[i]] = p[i];
    for (int i = 1; i <= n; i++) {
        if (mp[c[i]]) res += mp[c[i]];
        else res += p[0];
    }
    cout << res << endl;
}
signed main()
{
    solve();
    return 0;
}

C - Standings

会卡精度,double就不能过全部数据,改成long double就AC了

AC代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#include<map>
#include<cmath>
#define int long long
using namespace std;
const int N = 2e5 + 10;
struct node {
    long double a, b;
    long double rate;
    int idx;
    bool operator<(const node& W)const {
        if (rate!=W.rate) return rate>W.rate;
        return idx<W.idx;
    }
}q[N];
void solve()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> q[i].a >> q[i].b;
    for (int i = 1; i <= n; i++) {
        q[i].idx = i;
        q[i].rate = q[i].a /(q[i].a + q[i].b);
    }
    sort(q + 1, q + 1 + n);
    for (int i = 1; i <= n; i++) cout << q[i].idx << " ";
}
signed main()
{
    solve();
    return 0;
}

D - Snuke Maze

用dfs

原本写的代码,各种tle以及re：

#include<iostream>
#include<algorithm>
#include<cstring>
#define int long long
using namespace std;
const int N=510;
char s[N][N];
bool check(char ch1,char ch2){
    if(ch1=='s'&&ch2=='n') return true;
    if(ch1=='n'&&ch2=='u') return true;
    if(ch1=='u'&&ch2=='k') return true;
    if(ch1=='k'&&ch2=='e') return true;
    if(ch1=='e'&&ch2=='s') return true;
    return false; 
}
int res;
int h,w;
bool found;
void dfs(int x,int y){
    if(x==h&&y==w){
        res++;
        found=true;
        return;
    }
    if(found) return;
    if(x-1>=1&&check(s[x][y],s[x-1][y])) dfs(x-1,y);
    if(y-1>=1&&check(s[x][y],s[x][y-1])) dfs(x,y-1);
    if(x+1<=h&&check(s[x][y],s[x+1][y])) dfs(x+1,y);
    if(y+1<=w&&check(s[x][y],s[x][y+1])) dfs(x,y+1);
}
void solve()
{
    cin>>h>>w;
    for(int i=1;i<=h;i++){
        for(int j=1;j<=w;j++){
            cin>>s[i][j];
        }
    }
    if(s[1][1]!='s'){
        puts("No");
        return;
    }
    dfs(1,1);
    if(res) puts("Yes");
    else puts("No");
}
signed main()
{
    solve();
    return 0;
}

别人的代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#define int long long
using namespace std;
const int N=510;
char s[N][N];
int h,w;
string t="snuke";
int dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
int vis[N][N][5];
int res;
void dfs(int x,int y,int cur){
    if(x<1||y<1||x>h||y>w) return ;
    if(s[x][y]!=t[cur]) return ;
    if(x==h&&y==w){
        res++;
        return;
    }
    if(vis[x][y][cur]) return;
    vis[x][y][cur]=1;
    for(int i=0;i<4;i++){
        dfs(x+dx[i],y+dy[i],(cur+1)%5);
    }
}
void solve()
{
    cin>>h>>w;
    for(int i=1;i<=h;i++){
        for(int j=1;j<=w;j++){
            cin>>s[i][j];
        }
    }
    dfs(1,1,0);
    if(res) puts("Yes");
    else puts("No");
}
signed main()
{
    solve();
    return 0;
}

对比之后发现我的代码少了标记已经走过的点

进行修正

中间要注意剪枝

AC代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#define int long long
using namespace std;
const int N=510;
char s[N][N];
int vis[N][N];
bool check(char ch1,char ch2){
    if(ch1=='s'&&ch2=='n') return true;
    if(ch1=='n'&&ch2=='u') return true;
    if(ch1=='u'&&ch2=='k') return true;
    if(ch1=='k'&&ch2=='e') return true;
    if(ch1=='e'&&ch2=='s') return true;
    return false; 
}
int res;
int h,w;
bool found;
void dfs(int x,int y){
    if(x==h&&y==w){
        res++;
        found=true;
        return;
    }
    if(vis[x][y]) return;
    vis[x][y]=1;
    if(found) return;
    if(x-1>=1&&check(s[x][y],s[x-1][y])) dfs(x-1,y);
    if(y-1>=1&&check(s[x][y],s[x][y-1])) dfs(x,y-1);
    if(x+1<=h&&check(s[x][y],s[x+1][y])) dfs(x+1,y);
    if(y+1<=w&&check(s[x][y],s[x][y+1])) dfs(x,y+1);
}
void solve()
{
    cin>>h>>w;
    for(int i=1;i<=h;i++){
        for(int j=1;j<=w;j++){
            cin>>s[i][j];
        }
    }
    if(s[1][1]!='s'){
        puts("No");
        return;
    }
    dfs(1,1);
    if(res) puts("Yes");
    else puts("No");
}
signed main()
{
    solve();
    return 0;
}