题目链接：http://poj.org/problem?id=1088
#include <stdio.h>
#include <vector>
#include <algorithm>
#include <queue>
#include <functional>
using namespace std;//POJ 1088 滑雪int maxPath[102][102];
int matrix[102][102];struct MyGreater {bool operator()(const pair<int, pair<int, int> >& lhs, const pair<int, pair<int, int> >& rhs) {return lhs.first >= rhs.first;}
};inline int max4(int v[4])
{int max = v[0];if (max < v[1])max = v[1];if (max < v[2])max = v[2];if (max < v[3])max = v[3];return max;
}int main()
{int R, C;scanf("%d%d", &R, &C);vector<pair<int, pair<int, int> > > c(R*C);int count = 0;for (int i = 1; i <= R; i++)for (int j = 1; j <= C; j++){scanf("%d", &matrix[i][j]);c[count++] = make_pair(matrix[i][j], make_pair(i, j));maxPath[i][j] = 1; // no way to go}priority_queue <pair<int, pair<int, int> >, vector<pair<int, pair<int, int> > >, MyGreater>pq(MyGreater(), c);int max_path = 0;while (!pq.empty()){pair<int, pair<int, int> > p = pq.top(); pq.pop();int h = p.first, x = p.second.first, y = p.second.second;int v[4];v[0] = matrix[x - 1][y] >= h ? -1 : maxPath[x - 1][y];v[1] = matrix[x + 1][y] >= h ? -1 : maxPath[x + 1][y];v[2] = matrix[x][y - 1] >= h ? -1 : maxPath[x][y - 1];v[3] = matrix[x][y + 1] >= h ? -1 : maxPath[x][y + 1];maxPath[x][y] = max4(v);if (maxPath[x][y] < 0) maxPath[x][y] = 1; // no way to goelse maxPath[x][y]++;max_path = max(max_path, maxPath[x][y]);}printf("%d", max_path);system("pause");return 0;
}