HDU5583 Kingdom of Black and White

来源：互联网发布：韧带知乎编辑：程序博客网时间：2024/05/22 05:02

题目：
给一串01字符串，至多改变其中一个（0->1/1->0/不改变），求操作完成后，连续符号（连续0/连续1）长度的平方和最大值
分析：
我啥也不想说！
就一个字：所有变量开long long！！！调了两天！
以后长记性！
代码：

#include <cstdio>#include <algorithm>#include <cstring>#include <cmath>using namespace std;const int Tmax=100005;long long int ans,sum;char data[Tmax];long long lzero[Tmax],lone[Tmax],rzero[Tmax],rone[Tmax],n;void init(){    int i,zero=0,one=0;    for(i=0;i<n;i++)    {        lzero[i]=zero;        lone[i]=one;        if(data[i]=='0')        {            zero++;            one=0;        }        else{            one++;            zero=0;        }    }    zero=one=0;    for(i=n-1;i>=0;i--)    {        rzero[i]=zero;        rone[i]=one;        if(data[i]=='0')        {            zero++;            one=0;        }        else{            one++;            zero=0;        }    }    return;}void work(){    int i;    if(data[0]!=data[1])    {        if(data[1]=='0')          ans=max(ans,sum-1-rzero[0]*rzero[0]+(rzero[0]+1)*(rzero[0]+1));        else ans=max(ans,sum-1-rone[0]*rone[0]+(rone[0]+1)*(rone[0]+1));    }    for(i=1;i<n-1;i++)    {        if(data[i-1]==data[i+1]&&data[i-1]==data[i]) continue;        if(data[i-1]==data[i+1]&&data[i]!=data[i+1])        {            if(data[i]=='0') ans=max(ans,sum-lone[i]*lone[i]-rone[i]*rone[i]+(lone[i]+rone[i]+1)*(lone[i]+rone[i]+1)-1);            else ans=max(ans,sum-lzero[i]*lzero[i]-rzero[i]*rzero[i]+(lzero[i]+rzero[i]+1)*(lzero[i]+rzero[i]+1)-1);        }        else{            if(data[i]=='0'&&data[i-1]=='0') ans=max(ans,sum-(lzero[i]+1)*(lzero[i]+1)-rone[i]*rone[i]+lzero[i]*lzero[i]+(rone[i]+1)*(rone[i]+1));            else if(data[i]=='1'&&data[i-1]=='1') ans=max(ans,sum-(lone[i]+1)*(lone[i]+1)-rzero[i]*rzero[i]+lone[i]*lone[i]+(rzero[i]+1)*(rzero[i]+1));            else if(data[i]=='0'&&data[i-1]=='1') ans=max(ans,sum-lone[i]*lone[i]-(rzero[i]+1)*(rzero[i]+1)+(lone[i]+1)*(lone[i]+1)+rzero[i]*rzero[i]);            else ans=max(ans,sum-lzero[i]*lzero[i]-(rone[i]+1)*(rone[i]+1)+(lzero[i]+1)*(lzero[i]+1)+rone[i]*rone[i]);        }    }    if(data[n-1]!=data[n-2])    {        if(data[n-2]=='0')          ans=max(ans,sum-1-lzero[n-1]*lzero[n-1]+(lzero[n-1]+1)*(lzero[n-1]+1));        else ans=max(ans,sum-1-lone[n-1]*lone[n-1]+(lone[n-1]+1)*(lone[n-1]+1));    }    return;}void check(){    int i;    long long num=1;    sum=0;    for(i=1;i<n;i++)    {        if(data[i]==data[i-1]) num++;        else{            sum+=num*num;            num=1;        }    }    sum+=num*num;    ans=sum;    return;}int main(){    int T,kase;    scanf("%d",&T);    for(kase=1;kase<=T;kase++)    {        scanf("%s",data);        n=strlen(data);        check();        init();        work();        printf("Case #%d: %I64d\n",kase,ans);    }    return 0;}

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