Ultraviolet A 1330-City game

Question link:

Http://uva.onlinejudge.org/index.php? Option = com_onlinejudge & Itemid = 8 & category = 460 & page = show_problem & problem = 4076

I have done a one-dimensional problem before. This problem is only two-dimensional, and other methods are the same. HDU 1506 largest rectangle in a Histogram

Code 1:

#include<cstdio>#include<cstring>#include<stack>using std::stack;const int MAXN = 1010;char str[MAXN*3];int sum[MAXN][MAXN];int left[MAXN], right[MAXN];int n, m;inline void input(){    scanf("%d%d%*c", &n, &m);    for(int i=1; i<=n; ++i){        for(int j=1; j<=m; ++j){            char ch = getchar();            while(ch!='F' && ch!='R') ch=getchar();            sum[i][j] = ch=='R'?0:1;            if(sum[i][j]) sum[i][j] += sum[i-1][j];        }    } }inline void solve(){    input();     int ans = 0;    for(int i=1; i<=n; ++i){        sum[i][0] = sum[i][m+1] = -1;        for(int j=1; j<=m; ++j)             left[j]=right[j]=j;        for(int j=1; j<=m; ++j){            while(sum[i][j] <= sum[i][left[j]-1])                left[j] = left[left[j]-1];        }        for(int j=m; j>=1; --j){            while(sum[i][j] <= sum[i][right[j]+1])                right[j] = right[right[j]+1];            int tmp = (right[j]-left[j]+1)*sum[i][j];            if(tmp > ans) ans=tmp;        }    }    printf("%d\n", ans*3);}int main(){    int nCase;    scanf("%d", &nCase);    while(nCase--){               solve();    }    return 0;} 

Code 2 (stack scan ):

#include<cstdio>#include<cstring>#include<stack>using std::stack;const int MAXN = 1010;char str[MAXN*3];int sum[MAXN][MAXN];int n, m;inline void input(){    scanf("%d%d%*c", &n, &m);    memset(sum, 0, sizeof(sum));    for(int i=1; i<=n; ++i){        for(int j=1; j<=m; ++j){            char ch = getchar();            while(ch!='F' && ch!='R') ch=getchar();            sum[i][j] = ch=='R'?0:1;            if(sum[i][j]) sum[i][j] += sum[i-1][j];        }    } }inline void solve(){    input();     int ans = 0;    for(int i=1; i<=n; ++i){        sum[i][0] = sum[i][m+1] = -1;        stack<int>q;        for(int j=1; j<=m+1; ++j){            if(q.empty() || sum[i][j]>sum[i][q.top()]){                q.push(j);            }            else if(sum[i][j] < sum[i][q.top()]){                int pos;                while(!q.empty() && sum[i][q.top()]>sum[i][j]){                    int tmp = (j-q.top())*sum[i][q.top()];                    if(tmp > ans)                        ans = tmp;                    pos = q.top();                    q.pop();                }                q.push(pos);                sum[i][pos] = sum[i][j];            }        }    }    printf("%d\n", ans*3);}int main(){    int nCase;    scanf("%d", &nCase);    while(nCase--){               solve();    }    return 0;}