"触宝CooTek杯” USTC Monthly Contest 2011-11-26 B&&E

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B题树状数组：

#include<iostream>#include<stdio.h>#include<stdlib.h>#include<string.h>#include<math.h>#include<algorithm>#include<vector>using namespace std;#define MAXN 1000005int c[MAXN]; void init()     {    memset(c,0,sizeof(c));}int Lowbit(int t){    return t&(-t);    }void add(int pos,int val){    for( ;pos<=MAXN;c[pos]+=val,pos+=Lowbit(pos));}int getsum(int end){    int sum=0;    for( ;end>0;sum+=c[end],end-=Lowbit(end));    return sum;}int main(){    int a,b;    char str[5];    init();    while(scanf("%s%d%d",str,&a,&b)!=EOF)    {        if(str[0]=='p')            add(a,b);        else if(str[0]=='c')            add(a,-b);        else        {            if(a>b)    swap(a,b);            printf("%d\n",getsum(b)-getsum(a-1));        }    }    return 0;}

E题简单DP：

#include<iostream>#include<stdio.h>#include<stdlib.h>#include<string.h>#include<math.h>#include<algorithm>#include<map>#include<string>#include<iomanip>#include<vector> using namespace std;#define MAX 1005int a[MAX][MAX],leftUp[MAX][MAX],rightUp[MAX][MAX],n,m,i,j;void init(){for(j=1;j<=m;j++)leftUp[1][j]=rightUp[1][j]=a[1][j];for(i=1;i<=n;i++)leftUp[i][1]=rightUp[i][1]=a[i][1];}int dp(){int ans=0;for(i=2;i<=n;i++)for(j=2;j<=m;j++){if(a[i][j]){leftUp[i][j]=leftUp[i-1][j-1]+1;if(j<m)rightUp[i][j]=rightUp[i-1][j+1]+1;elserightUp[i][j]=a[i][j];}elseleftUp[i][j]=rightUp[i][j]=0;if(leftUp[i][j]>1 && rightUp[i][j]>1)ans=max(ans,leftUp[i][j]+rightUp[i][j]-1);}return ans;}int main(){int t,ans;scanf("%d",&t);while(t--){scanf("%d%d",&n,&m);for(i=1;i<=n;i++)for(j=1;j<=m;j++)scanf("%d",&a[i][j]);init();ans=dp();printf("%d\n",ans>=3?ans:-1);}return 0;}