四川省赛

frog has n integers a1,a2,…,an, and she wants to add them pairwise.

 

Unfortunately, frog is somehow afraid of carries (进位). She defines \emph{hardness} h(x,y) for adding x and y the number of carries involved in the calculation. For example, h(1,9)=1,h(1,99)=2.

 

Find the total hardness adding n integers pairwise. In another word, find

∑1≤i<j≤nh(ai,aj)

.

//B  统计进位  就是说n个数  如果他们相加需要进位的话就加1   求所有俩俩之间的进位和/*#include<iostream>#include<cstdio>#include<cstring>#include<cstdlib>#include<algorithm>#include<cmath>#include<queue>#include<stack>#include<map>#include<set>#include<vector>using namespace std;typedef long long ll;#define inf 0x3f3f3f3f#define eps 1e-10#define maxl 100010#define mem(i,j) memset(i,j,sizeof(i))int a[maxl],d[maxl][15];int main(){    freopen("in.txt", "r", stdin);    int n;    while(scanf("%d",&n)!=EOF){        memset(d,0,sizeof(d));        for(int i=0;i<n;i++) {            scanf("%d",&a[i]);            int temp=a[i];            int cnt=0;            while(temp){                d[i][cnt++]=temp%10;                temp/=10;            }        }        ll ans=0;        vector<int> v;        for(int i=0;i<=10;i++){            v.clear();            for(int j=0;j<n;j++){                int res=0;                for(int k=i;k>=0;k--){                    res=res*10+d[j][k];                }                v.push_back(res);            }            ll sum=1;            for(int j=0;j<=i;j++) sum*=10;            sort(v.begin(),v.end());            for(int j=0;j<v.size();j++){                ans+=v.size()-(lower_bound(v.begin()+j+1,v.end(),sum-v[j])-v.begin());            }        }        printf("%lld\n",ans);    }}*/

frog has a graph with \(n\) vertices \(v(1), v(2), \dots, v(n)\) and \(m\) edges \((v(a_1), v(b_1)), (v(a_2), v(b_2)), \dots, (v(a_m), v(b_m))\).

 

She would like to color some vertices so that each edge has at least one colored vertex.

 

Find the minimum number of colored vertices.

//D   就是一个图  不一定是联通的  让你给点染色  保证所有的边都有至少一个点被染色了/*#include<iostream>#include<cstdio>#include<cstring>#include<cstdlib>#include<algorithm>#include<cmath>#include<queue>#include<stack>#include<map>#include<set>#include<vector>using namespace std;typedef long long ll;#define inf 0x3f3f3f3f#define eps 1e-10#define maxl 510#define mem(i,j) memset(i,j,sizeof(i))int d[maxl][maxl];int res[maxl],vis[maxl];int n,m,ans;bool solve(int u){    for(int v=1;v<=n;v++){        if(vis[v]||!d[u][v]) continue;        vis[v]=1;        if(res[v]==0||solve(res[v])){//二分图            res[v]=u;            return true;        }    }    return false;}int main(){    freopen("in.txt", "r", stdin);    while(scanf("%d%d",&n,&m)!=EOF){        memset(d,0,sizeof(d));        memset(res,0,sizeof(res));        ans=0;        int u,v;        for(int i=0;i<m;i++){            scanf("%d%d",&u,&v);            if(d[u][v]) continue;            d[u][v]=1;d[v][u]=1;        }        for(int i=1;i<=n;i++){            memset(vis,0,sizeof(vis));            if(solve(i)) ans++;        }        printf("%d\n",ans/2);    }}*/