City Game[单调栈]

传送门

记录可以最高到哪里 , 左右到哪里 , 然后更新答案

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#include<cstdio>
#include<stack>
#include<cstring>
#define N 1050
using namespace std;
int k,h[N],l[N],r[N],n,m,ans;
void Calc(){
	stack<int> S;
	memset(l,0,sizeof(l));
	memset(r,0,sizeof(r));
	for(int i=1;i<=m;i++){
		while(!S.empty() && h[i]<=h[S.top()]) S.pop();
		if(!S.empty()) l[i] = S.top(); 
		else l[i] = 0; S.push(i);
	}
	while(!S.empty()) S.pop();
	for(int i=m;i>=1;i--){
		while(!S.empty() && h[i]<=h[S.top()]) S.pop();
		if(!S.empty()) r[i] = S.top();
		else r[i] = m+1; S.push(i);
	}
	for(int i=1;i<=m;i++) ans = max(ans , ((r[i]-1)-(l[i]+1)+1) * h[i]);
}
int main(){
	scanf("%d",&k); while(k--){
		memset(h,0,sizeof(h)); ans = 0;
		scanf("%d%d",&n,&m);
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++){
				char ch; 
				while(ch=getchar()){if(ch=='R' || ch=='F') break;}
				if(ch=='F') h[j]++; else h[j]=0; 
			}Calc();
		}printf("%d\n",ans*3);
	} return 0;
}