2019.8.19 模拟赛

无聊的倒序 模拟

#include<bits/stdc++.h>
using namespace std;
int n,ans,x;
int main(){
    scanf("%d",&n);
    for(int i = 1; i <= n; i++){
        scanf("%d",&x);
        ans = 0;
        while(x){
            ans =ans*10 + x % 10;   
            x /= 10;
        }
        printf("%d\n",ans);
    }
    return 0;
}

 

节约的alice 贪心

#include<iostream>
#include<cstdio>
using namespace std;
int n,k,a[10];
int main(){
  scanf("%d",&n);
  a[++k] = n/100;
  n = n % 100;
  a[++k] = n/50;
  n = n % 50;
  a[++k] = n/20;
  n = n % 20;
  a[++k] = n / 10;
  n = n % 10;
  a[++k] = n / 5;
  n = n % 5;
  a[++k] = n;
  for(int i = k; i >=1; i--)
    printf("%d ",a[i]);
  return 0;
}

新扫雷游戏 递推

#include<bits/stdc++.h>
using namespace std;
int a[100005],b[100005],ans; 
void f(int n){
    int fl = 0;
    for(int i = 3; i <= n; i++){
        b[i] = a[i - 1] - b[i - 1] - b[i - 2];
        if(b[i] > 1 || b[i] < 0){
            fl = 1;break;
        }
    }
    if(fl == 0 && b[n - 1] + b[n] == a[n]) ans++;
}
int t,n; 
int main(){
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        ans = 0;
        for(int i = 1; i <= n; i++){
            scanf("%d",&a[i]); 
        }
        //如果是0或者2,则要不方案为1要么方案为0
        if(a[1] == 0) {
            b[1] = 0; b[2] = 0; f(n);
    
        }
        else if(a[1] == 2){
            b[1] = 1; b[2] = 1; f(n);
        }
        else if(a[1] == 1){//如果第一个数是1，则最多两种方法，分类判断是否成立 
            b[1] = 0; b[2] = 1; f(n);
            b[1] = 1; b[2] = 0; f(n);
        }
        printf("%d\n",ans);
    }
    return 0;
} 

 最短路转bfs问题

#include<bits/stdc++.h>
using namespace std;
int n,m,t,x,y,l,hd[10000005],cnt,dis[10000005],vis[10000005];
queue<int> q;
struct Node{
    int to,nxt;
}edge[40000005];
void add(int u,int v){
    cnt++;
    edge[cnt].to = v;
    edge[cnt].nxt = hd[u];
    hd[u] = cnt;
}
void bfs(){
    dis[1] = 0; vis[1] = 1; q.push(1);
    while(!q.empty()){
        int u = q.front(); q.pop();
//        cout<<u<<endl;
        for(int i = hd[u]; i; i = edge[i].nxt){
            int v = edge[i].to;
            if(vis[v]) continue;
            dis[v] = dis[u] + 1; 
//            cout<<v<<" "<<dis[v]<<endl;
            if(v == t){
                printf("%d\n",dis[v]);
                return;
            }
            vis[v] = 1;
            q.push(v);
        }
//        cout<<endl;
    }
    return ;
}
int k = 0;
int main(){
    scanf("%d%d%d",&n,&m,&t);
    for(int i = 1; i <= m; i++){
        scanf("%d%d%d",&x,&y,&l);
        if(l == 2) {
            add(x, n + (++k));
            add(n + k, y);
            add(y, n + k);
            add(n + k, x);
        }else{
            add(x,y);
            add(y,x);
        }
    }
//    for(int j = hd[6] ; j ; j = edge[j].nxt)
//        cout<<edge[j].to<<endl;
    bfs();
    return 0;
}