A

POJ 1321
acwing链接

#include <iostream> 
#include <cstring>
using namespace std;
int n,k;
char map[90][90];
int cnt;
int l[90];
//每一行选择放还是不放
//若放 则遍历到可以放置的位置 进入下一层
//不放直接进入下一层
void dfs(int u,int z){
    if (n-u+z<k) return ;
//剪枝 如果已经放了的加上最大可放数小于k 那么可以跳过了    
    if (z==k) {
        cnt++;
        return ;
    }
    if (u==n) return ;
    for (int i=0;i<n;i++){
        if (map[u][i]=='#'&&l[i]==0){
            l[i]=1;
            dfs(u+1,z+1);
            l[i]=0;
            //dfs(u+1,z);
        }
    }
    dfs(u+1,z);
}
int main (){
    while (1){
        scanf ("%d%d",&n,&k);
        if (n==-1) break;
        for (int i=0;i<n;i++){
            for (int j=0;j<n;j++) cin>>map[i][j];
        }
        cnt=0;
        memset(l,0,sizeof l);
        dfs(0,0);
        cout<<cnt<<endl;
    }
    return 0;
}

B

poj2251
acwing链接
bfs模板题 只是换成三维了而已

#include <iostream> 
#include <cstring>
#include <queue> 
#include <cstdio>
#define f first
#define s second
using namespace std;
char map[110][110][110];
int l,n,m;
bool mps[110][110][110];
int d[110][110][110];
int ls1,ns1,ms1,ls2,ns2,ms2;
int bfs(){
    queue <pair<pair<int,int> ,int> > q;
    q.push({{ls1,ns1},ms1});
    while (q.size()){
        pair<pair<int,int> ,int> t=q.front();
        q.pop();
        int dx[]={1,-1,0,0,0,0},dy[]={0,0,1,-1,0,0},dz[]={0,0,0,0,1,-1};
        for (int i=0;i<6;i++){
            int x=t.f.f+dx[i],y=t.f.s+dy[i],z=t.s+dz[i];
            if (x>=0&&x<l&&y>=0&&y<n&&z>=0&&z<m&&d[x][y][z]==-1&&(map[x][y][z]=='.'||map[x][y][z]=='E')){
                d[x][y][z]=d[t.f.f][t.f.s][t.s]+1;
                q.push({{x,y},z});
            }
        }
    }
    return d[ls2][ns2][ms2];
}
int main (){
    while (1){
        cin>>l>>n>>m;
        if (l==0) break;
        memset(d,-1,sizeof d);
        for (int i=0;i<l;i++){
            for (int j=0;j<n;j++){
                for (int k=0;k<m;k++){
                    cin>>map[i][j][k];
                    if (map[i][j][k]=='S') {
                        ls1=i,ns1=j,ms1=k;
                        d[i][j][k]=0;
                    }
                    if (map[i][j][k]=='E'){
                        ls2=i,ns2=j,ms2=k;
                    }
                }
            }
            //cout<<l<<endl;
        }
        int t=bfs();
        if (t!=-1) printf ("Escaped in %d minute(s).\n",t);
        else cout<<"Trapped!"<<endl;
    }
    return 0;
}

C

poj3278
acwing链接

#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <queue>
using namespace std;
int x,k;
int d[100010];
int bfs(){
    queue <int> q;
    q.push(x);
    memset(d,-1,sizeof d);
    d[x]=0;
    while (q.size()){
        int t=q.front();
        q.pop();
        int dx[]={1,-1,t};
        for (int i=0;i<3;i++){
            int a=t+dx[i];
            if (a>=0&&a<=100000&&d[a]==-1){
                q.push(a);
                d[a]=d[t]+1;
            }
        }
    }
    return d[k];
}
int main (){
    scanf ("%d%d",&x,&k);
    int t;
    t=bfs();
    cout<<t;
    return 0;
}

D

poj3279

#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <queue>
using namespace std;
int n,m; 
int map[20][20],ans[20][20];
void turn(int x,int y){
    int dx[]={0,1,-1,0,0},dy[]={0,0,0,1,-1};
    for (int i=0;i<5;i++){
        int a=x+dx[i],b=y+dy[i];
        if (a>=0&&a<n&&b>=0&&b<m){
            map[a][b]=(map[a][b]+1)%2;
            //ans[a][b]=1;
        }
    }
}
bool check(){
    for (int i=n-1;i<n;i++){
        for (int j=0;j<m;j++){
            if (map[i][j]==1) return false;
        }
    }
    return true;
}
int main (){
    cin>>n>>m;
    for (int i=0;i<n;i++){
        for (int j=0;j<m;j++){
            scanf ("%d",&map[i][j]);
        }
    }
    int mins=890;
    int ans2[20][20];
    for(int i=0;i<1<<n;i++){
        int t=i;
        int u=0;
        int cnt=0;
        int g[20][20];
        int g2[20][20];
        memcpy(g,map,sizeof map);
        memcpy(g2,ans,sizeof g2);
        while (t){
            if (t&1) {
                turn(0,u);
                cnt++;
                //cout<<u<<' ';
                ans[0][u]=1;
            }
            u++;
            t>>=1;
        }
        //cout<<endl;
        for (int i=1;i<n;i++){
            for (int j=0;j<m;j++){
                if (map[i-1][j]==1) {
                    turn(i,j);
                    ans[i][j]=1;
                    cnt++;
                    //cout<<i<<j<<' ';
                }
                //cout<<endl;
            }
        }
        //cout<<endl;
        if (check()) {
            //mins=min(mins,cnt);
            if (mins>cnt){
                mins=cnt;
                //cout<<cnt<<' ';
                memcpy(ans2,ans,sizeof ans);
            }
        }
        memcpy(map,g,sizeof g);
        memcpy(ans,g2,sizeof g2);
    }
    if (mins<890) {
        for (int i=0;i<n;i++){
            for (int j=0;j<m;j++){
                cout<<ans2[i][j]<<' ';
            }
            cout<<endl;
        }       
    }
    else printf ("IMPOSSIBLE\n");
    //cout<<mins;
    return 0;
}

E

poj1426

#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <queue>
using namespace std;
unsigned long long ans;
int n,p;
void dfs(unsigned long long x,int k){
    if (p==1) return ;
    if (x%n==0){
        p=1;
        //ans=x;
        //cout<<x<
        printf ("%llu\n",x);
        return ;
    }
    if (k==19) return ;
    dfs(x*10,k+1);
    dfs(x*10+1,k+1);
}
int main (){
    while(1){
        scanf ("%d",&n);
        if (!n) break;
        p=0;
        dfs(1,0);
        //cout<<ans<<endl;
    }
    return 0;
}

F

poj3126

#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <queue>
using namespace std;
int a[10000],cnt;
bool st[10000];
int x,y;
int d[10009];
bool lj[10000];
void get_prime(int n){
    for (int i=2;i<=n;i++){
        if (!st[i]) a[cnt++]=i;
        for (int j=0;a[j]<=n/i;j++){
            st[a[j]*i]=1;
            if (i%a[j]==0) break;
        }
    }
}
int bfs(){
    memset(d,-1,sizeof d);
    d[x]=0;
    queue <int> q;
    q.push(x);
    while (q.size()){
        int t=q.front();
        q.pop();
        int dx[]={0,1,2,3};
        int num[2000];
        int nums=0;
        for (int i=0;i<4;i++){
            //if (t==3739)cout<<'\n';
            for (int j=0;j<10;j++){
                int u=t;
                if (i==0) {
                    u=t/10*10+j; 
                }
                if (i==1) u=(t/100)*100+j*10+u%10;
                if (i==2) u=(t-(t/100%10)*100)+j*100;
                if (i==3&&j>=1)  u=j*1000+u%1000;
                //if (t==3739)cout<<u<<' ';
                if (u>1000&&u<10000&&u!=t){
                    if(!st[u]){
                        num[nums++]=u;
                    }
                }
            }
        }
        for (int i=0;i<nums;i++){
            if (d[num[i]]!=-1) {
                if (d[num[i]]>d[t]+1) {
                    d[num[i]]=d[t]+1;
                    q.push(num[i]);
                }
            }
            else {
                d[num[i]]=d[t]+1;
                q.push(num[i]);
            }
        }
    }
    return d[y];
}
int main (){
    int m;
    cin>>m;
    get_prime(10000);
    while (m--){
        scanf ("%d %d",&x,&y);
        int z=bfs();
        if (z!=-1)cout<<z<<endl;
        else printf ("Impossible\n");
    }
    return 0;
}

G

poj3087

//我以为是个搜索题 结果是个模拟题
//应以为戒 思考问题要全面
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <queue>
// #include <unordered_set>
// #include <unordered_map>
//poj好像不支持c++11
#define f first
#define s second
using namespace std;

int t,n;
string a,b,ans; 
int cs;
int main (){
    cin>>t;
    int z=0;
    while (t--){
        z++;
        scanf ("%d",&n);
        cin>>a>>b>>ans;
        string u;
        for (int i=0;i<n;i++) {
            u+=b[i];
            u+=a[i];
        }
        int i;
        string t=u;
        int p=1;
        for (i=1;t!=ans;i++){
            string ss=t;
            string a1=ss.substr(0,n),b1=ss.substr(n);
            string s2;
            for (int j=0;j<n;j++){
                s2+=b1[j];
                s2+=a1[j];
            }
            if (s2==u) {
                p=0;
                break;
            }
            t=s2;
        }
        if (p) printf ("%d %d\n",z,i);
        else printf ("%d %d\n",z,-1);
    }
    return 0;
}