From 448a61349cb8b44ad2d4fa508c673a248b274259 Mon Sep 17 00:00:00 2001
From: YDZ <ydz627@gmail.com>
Date: Mon, 30 Dec 2019 20:59:38 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20problem=20329?=
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---
 ...29. Longest Increasing Path in a Matrix.go | 42 ++++++++++++
 ...ongest Increasing Path in a Matrix_test.go | 67 +++++++++++++++++++
 .../README.md                                 | 42 ++++++++++++
 3 files changed, 151 insertions(+)
 create mode 100644 Algorithms/0329. Longest Increasing Path in a Matrix/329. Longest Increasing Path in a Matrix.go
 create mode 100644 Algorithms/0329. Longest Increasing Path in a Matrix/329. Longest Increasing Path in a Matrix_test.go
 create mode 100755 Algorithms/0329. Longest Increasing Path in a Matrix/README.md

diff --git a/Algorithms/0329. Longest Increasing Path in a Matrix/329. Longest Increasing Path in a Matrix.go b/Algorithms/0329. Longest Increasing Path in a Matrix/329. Longest Increasing Path in a Matrix.go
new file mode 100644
index 00000000..791df53b
--- /dev/null
+++ b/Algorithms/0329. Longest Increasing Path in a Matrix/329. Longest Increasing Path in a Matrix.go	
@@ -0,0 +1,42 @@
+package leetcode
+
+import (
+	"math"
+)
+
+func longestIncreasingPath(matrix [][]int) int {
+	cache, res := make([][]int, len(matrix)), 0
+	for i := 0; i < len(cache); i++ {
+		cache[i] = make([]int, len(matrix[0]))
+	}
+	for i, v := range matrix {
+		for j := range v {
+			searchPath(matrix, cache, math.MinInt64, i, j)
+			res = max(res, cache[i][j])
+		}
+	}
+	return res
+}
+
+func isInIntBoard(board [][]int, x, y int) bool {
+	return x >= 0 && x < len(board) && y >= 0 && y < len(board[0])
+}
+
+func searchPath(board, cache [][]int, lastNum, x, y int) int {
+	if board[x][y] <= lastNum {
+		return 0
+	}
+	if cache[x][y] > 0 {
+		return cache[x][y]
+	}
+	count := 1
+	for i := 0; i < 4; i++ {
+		nx := x + dir[i][0]
+		ny := y + dir[i][1]
+		if isInIntBoard(board, nx, ny) {
+			count = max(count, searchPath(board, cache, board[x][y], nx, ny)+1)
+		}
+	}
+	cache[x][y] = count
+	return count
+}
diff --git a/Algorithms/0329. Longest Increasing Path in a Matrix/329. Longest Increasing Path in a Matrix_test.go b/Algorithms/0329. Longest Increasing Path in a Matrix/329. Longest Increasing Path in a Matrix_test.go
new file mode 100644
index 00000000..4d8d754d
--- /dev/null
+++ b/Algorithms/0329. Longest Increasing Path in a Matrix/329. Longest Increasing Path in a Matrix_test.go	
@@ -0,0 +1,67 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question329 struct {
+	para329
+	ans329
+}
+
+// para 是参数
+// one 代表第一个参数
+type para329 struct {
+	matrix [][]int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans329 struct {
+	one int
+}
+
+func Test_Problem329(t *testing.T) {
+
+	qs := []question329{
+
+		question329{
+			para329{[][]int{[]int{1}}},
+			ans329{1},
+		},
+
+		question329{
+			para329{[][]int{[]int{}}},
+			ans329{0},
+		},
+
+		question329{
+			para329{[][]int{[]int{9, 9, 4}, []int{6, 6, 8}, []int{2, 1, 1}}},
+			ans329{4},
+		},
+
+		question329{
+			para329{[][]int{[]int{3, 4, 5}, []int{3, 2, 6}, []int{2, 2, 1}}},
+			ans329{4},
+		},
+
+		question329{
+			para329{[][]int{[]int{1, 5, 9}, []int{10, 11, 13}, []int{12, 13, 15}}},
+			ans329{5},
+		},
+
+		question329{
+			para329{[][]int{[]int{1, 5, 7}, []int{11, 12, 13}, []int{12, 13, 15}}},
+			ans329{5},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 329------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans329, q.para329
+		fmt.Printf("【input】:%v       【output】:%v\n", p, longestIncreasingPath(p.matrix))
+	}
+	fmt.Printf("\n\n\n")
+}
diff --git a/Algorithms/0329. Longest Increasing Path in a Matrix/README.md b/Algorithms/0329. Longest Increasing Path in a Matrix/README.md
new file mode 100755
index 00000000..116aa4aa
--- /dev/null
+++ b/Algorithms/0329. Longest Increasing Path in a Matrix/README.md	
@@ -0,0 +1,42 @@
+# [329. Longest Increasing Path in a Matrix](https://leetcode.com/problems/longest-increasing-path-in-a-matrix/)
+
+
+## 题目:
+
+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:**
+
+    Input: nums = 
+    [
+      [9,9,4],
+      [6,6,8],
+      [2,1,1]
+    ] 
+    Output: 4 
+    Explanation: The longest increasing path is [1, 2, 6, 9].
+
+**Example 2:**
+
+    Input: nums = 
+    [
+      [3,4,5],
+      [3,2,6],
+      [2,2,1]
+    ] 
+    Output: 4 
+    Explanation: The longest increasing path is [3, 4, 5, 6]. Moving diagonally is not allowed.
+
+
+## 题目大意
+
+给定一个整数矩阵，找出最长递增路径的长度。对于每个单元格，你可以往上，下，左，右四个方向移动。 你不能在对角线方向上移动或移动到边界外（即不允许环绕）。
+
+
+## 解题思路
+
+
+- 给出一个矩阵，要求在这个矩阵中找到一个最长递增的路径。路径有上下左右 4 个方向。
+- 这一题解题思路很明显，用 DFS 即可。在提交完第一版以后会发现 TLE，因为题目给出了一个非常大的矩阵，搜索次数太多。所以需要用到记忆化，把曾经搜索过的最大长度缓存起来，增加了记忆化以后再次提交 AC。