Google APAC 2016 University Graduates Test(google校招筆試)

Problem A. Bad Horse

題意：給n個關係，每個關係有兩個人，要求把這些人分成兩組，每組裏的人之間都沒有關係。

二分圖染色即可。關係=邊，人=點。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<queue>
#include<set>
#include<map>
#include<vector>
#include<cmath>
#define ll __int64
#define INF 0x3fffffff
using namespace std;

int G[105][105];
int col[105];
int k;

bool bfs(int s) {
    queue<int> p;
    p.push(s);
    col[s] = 1;
    while(!p.empty()) {
        int from = p.front();
        p.pop();
        for(int i = 1; i <= k; i++) {
            if(G[from][i] && col[i] == -1) {
                p.push(i);
                col[i] = !col[from];//染成不同的顏色
            }
            if(G[from][i] && col[from] == col[i])//顏色有相同，則不是二分圖
                return false;
        }
    }
    return true;
}

int main()
{
    //freopen("d:\\A-small-2-attempt0.in","r",stdin);
    //freopen("d:\\output.txt","w",stdout);
    int n,T,t=1;
    cin>>T;
    while(T--){
        cin>>n;
        k=0;
        map<string,int>m;
        memset(G,0,sizeof(G));
        memset(col, -1, sizeof(col));
        for(int i=0;i<n;i++){
            char a[105],b[105];
            cin>>a>>b;
            if(!m[a]) m[a]=++k;
            if(!m[b]) m[b]=++k;
            G[m[a]][m[b]]=1;
            G[m[b]][m[a]]=1;
        }
        bool flag=false;
        for(int i=1;i<=k;i++){
            if(col[i]==-1&&!bfs(i)){
                flag=true;
                break;
            }
        }
        if(!flag) cout<<"Case #"<<t++<<": "<<"Yes"<<endl;
        else cout<<"Case #"<<t++<<": "<<"No"<<endl;
    }
    return 0;
}<strong>
</strong>

Problem B. Captain Hammer

題意：給出斜拋運動的速度和水平位移，求斜拋角度。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<queue>
#include<set>
#include<map>
#include<vector>
#include<cmath>
#define ll __int64
#define INF 0x3fffffff
using namespace std;

int main()
{
    //freopen("d:\\Test.txt","r",stdin);
    //freopen("d:\\output.txt","w",stdout);
    int T,t=1;
    cin>>T;
    while(T--){
        double v,d,c;
        cin>>v>>d;
        c=asin(9.8*d/v/v) * 180.0/3.1415926/2.0;
        cout<<"Case #"<<t++<<": ";
        printf("%.7f\n",c);
    }
    return 0;
}

Problem C. Moist

題意：給n個字符串，要求按字典序排序，排序方法爲從上往下掃，遇到一個比上面裏的小的，就交換位置。求交換次數

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cstdlib>
#include<algorithm>
#include<queue>
#include<set>
#include<map>
#include<vector>
#include<cmath>
#define ll __int64
#define INF 0x3fffffff
using namespace std;

char s[105][105];
int n;

int main()
{
    //freopen("d:\\C-small-2-attempt0.in","r",stdin);
    //freopen("d:\\output.txt","w",stdout);
    int T,t=1;
    cin>>T;
    while(T--){
        cin>>n;
        getchar();
        for(int i=0;i<n;i++){
            gets(s[i]);
        }
        int ans=0;
        for(int i=0;i<n;i++){
            for(int j=0;j<i;j++){
                if(strcmp(s[j],s[i])>0){
                    swap(s[j],s[i]);
                    ans++;
                    break;
                }
            }
        }
        cout<<"Case #"<<t++<<": "<<ans<<endl;
    }
    return 0;
}