[leetcode] 329. Longest Increasing Path in a Matrix 解题报告
2016-02-19 23:40
429 查看
题目链接:https://leetcode.com/problems/longest-increasing-path-in-a-matrix/
Given an integer matrix, find the length of the longest increasing path.
From each cell, you can either move to four directions: left, right, up or down. You may NOT move diagonally or move outside of the boundary (i.e. wrap-around is not allowed).
Example 1:
Return
The longest increasing path is
Example 2:
Return
The longest increasing path is
思路:DFS + 记忆化搜索
使用一个数组来记录已经搜索过的路径。调起来还是花了一些时间。
代码如下:
Given an integer matrix, find the length of the longest increasing path.
From each cell, you can either move to four directions: left, right, up or down. You may NOT move diagonally or move outside of the boundary (i.e. wrap-around is not allowed).
Example 1:
nums = [ [9,9,4], [6,6,8], [2,1,1] ]
Return
4
The longest increasing path is
[1, 2, 6, 9].
Example 2:
nums = [ [3,4,5], [3,2,6], [2,2,1] ]
Return
4
The longest increasing path is
[3, 4, 5, 6]. Moving diagonally is not allowed.
思路:DFS + 记忆化搜索
使用一个数组来记录已经搜索过的路径。调起来还是花了一些时间。
代码如下:
class Solution { public: int DFS(vector<vector<int>>& matrix, int y, int x, int val, vector<vector<int>>& hash) { if(y < 0 || y >= matrix.size() || x <0 || x >= matrix[0].size()) return 0; if(matrix[y][x] > val) { if(hash[y][x] != 0) return hash[y][x]; //if this path has been searched int a = DFS(matrix, y, x+1,matrix[y][x], hash) + 1; int b = DFS(matrix, y, x-1,matrix[y][x], hash) + 1; int c = DFS(matrix, y+1, x,matrix[y][x], hash) + 1; int d = DFS(matrix, y-1, x,matrix[y][x], hash) + 1; hash[y][x] = max(a, max(b,max(c, d))); return hash[y][x]; } return 0; } int longestIncreasingPath(vector<vector<int>>& matrix) { if(matrix.size() == 0) return 0; int Max = 0; vector<vector<int>> hash(matrix.size(), vector<int>(matrix[0].size(), 0)); for(int i = 0; i< matrix.size(); i++) for(int j = 0; j < matrix[0].size(); j++) Max = max(DFS(matrix, i, j, INT_MIN, hash), Max); return Max; } };
相关文章推荐
- selenium 操控浏览器
- [深入Python]sys.modules http://www.cnblogs.com/tuzkee/p/3540448.html
- mysql开启远程访问
- poj1010 dfs/枚举
- 蓝桥杯 十六进制转八进制
- 【线段树】【树】[BZOJ4293][HYSBZ4293][PA2015]Siano
- 移动零售批发行业新的技术特色-智能PDA手持移动扫描打印销售开单收银仪!!
- JFrame的setBackGround与getContentPane().setBackground区别
- 夺命雷公狗---微信开发24----客服消息接口基础和推送图片
- C 部分
- Counting Sheep(HDU2952)
- OC部分
- 堆排序
- 离屏表面
- poj 3414 Pots
- 【读书】二、单例模式
- 装修之卫生间的处理
- 简单的UIPickView功能
- 第38课:BlockManager架构原理、运行流程图和源码解密
- 第三百二十三天 how can I 坚持