这道题用到了悬线法，非常牛逼，可以看这个论文。
#include#include #include #include #define REP(i, a, b) for(int i = (a); i < (b); i++)#define _for(i, a, b) for(int i = (a); i <= (b); i++)using namespace std; const int MAXN = 2123;int l[MAXN][MAXN], r[MAXN][MAXN], h[MAXN][MAXN];int a[MAXN][MAXN], n, m; int main(){ scanf("%d%d", &n, &m); _for(i, 1, n) _for(j, 1, m) { char c; cin >> c; a[i][j] = (c == 'F'); h[i][j] = 1; l[i][j] = r[i][j] = j; } _for(i, 1, n) { _for(j, 2, m) if(a[i][j-1] && a[i][j]) l[i][j] = l[i][j-1]; for(int j = m - 1; j >= 1; j--) if(a[i][j+1] && a[i][j]) r[i][j] = r[i][j+1]; } int ans = 0; _for(i, 1, n) _for(j, 1, m) { if(i > 1 && a[i][j] && a[i-1][j]) { h[i][j] = h[i-1][j] + 1; l[i][j] = max(l[i][j], l[i-1][j]); r[i][j] = min(r[i][j], r[i-1][j]); } ans = max(ans, (r[i][j] - l[i][j] + 1) * h[i][j]); } printf("%d\n", 3 * ans); return 0;}