44 finish

Author: aQua

Algorithms/0044.wildcard-matching/README.md

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+# [44. Wildcard Matching](https://leetcode.com/problems/wildcard-matching/)
+
+## 题目
+Implement wildcard pattern matching with support for '?' and '*'.
+
+'?' Matches any single character.
+'*' Matches any sequence of characters (including the empty sequence).
+
+The matching should cover the entire input string (not partial).
+
+The function prototype should be:
+bool isMatch(const char *s, const char *p)
+
+Some examples:
+isMatch("aa","a") → false
+isMatch("aa","aa") → true
+isMatch("aaa","aa") → false
+isMatch("aa", "*") → true
+isMatch("aa", "a*") → true
+isMatch("ab", "?*") → true
+isMatch("aab", "c*a*b") → false
+
+## 解题思路
+注意审题：
+1. '?' 可以匹配任意一个字符，但是不能匹配空字符""
+1. '*' 可以任意多个字符，包括""
+
+见程序注释

Algorithms/0044.wildcard-matching/wildcard-matching.go

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+package Problem0044
+
+func isMatch(s string, p string) bool {
+	ls, lp := len(s), len(p)
+
+	dp := [][]bool{}
+	for i := 0; i < ls+1; i++ {
+		rt := make([]bool, lp+1)
+		dp = append(dp, rt)
+	}
+	// dp[i][j] == true 意味着，s[:i+1] 可以和 p[:j+1] 匹配
+	dp[0][0] = true
+
+	for j := 1; j <= lp; j++ {
+		if p[j-1] == '*' {
+			// 当 p[j-1] == '*' 时
+			// 只要前面的匹配，dp[0][j] 就匹配
+			// 一旦 p[j-1] != '*'，后面的 dp[0][j] 就都为 false
+			dp[0][j] = dp[0][j-1]
+		}
+	}
+
+	for i := 1; i <= ls; i++ {
+		for j := 1; j <= lp; j++ {
+			if p[j-1] != '*' {
+				// 当 p[j-1] != '*' 时
+				// 单个字符要匹配，并且之前的字符串也要匹配。
+				dp[i][j] = (p[j-1] == s[i-1] || p[j-1] == '?') && dp[i-1][j-1]
+			} else {
+				// 当 p[j-1] == '*' 时
+				//   要么，dp[i-1][j] == true，意味着，
+				//   当 s[:i] 与 p[:j+1] 匹配，且p[j] == '*' 的时候，
+				//   s[:i] 后接任意字符串的 s[:i+1] 仍与 p[:j+1] 匹配。
+				//   要么，dp[i][j-1] == true，意味着，
+				//   当 s[:i+1] 与 p[:j] 匹配后
+				//   在 p[:j] 后添加'*'，s[:i+1] 与 p[:j+1] 任然匹配
+				//   因为， '*' 可以匹配空字符。
+				dp[i][j] = dp[i-1][j] || dp[i][j-1]
+			}
+		}
+	}
+	return dp[ls][lp]
+}

Algorithms/0044.wildcard-matching/wildcard-matching_test.go

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+package Problem0044
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type question struct {
+	para
+	ans
+}
+
+// para 是参数
+type para struct {
+	s string
+	p string
+}
+
+// ans 是答案
+type ans struct {
+	one bool
+}
+
+func Test_Problem0044(t *testing.T) {
+	ast := assert.New(t)
+
+	qs := []question{
+
+		question{
+			para{
+				"aa",
+				"a",
+			},
+			ans{
+				false,
+			},
+		},
+
+		question{
+			para{
+				"aa",
+				"aa",
+			},
+			ans{
+				true,
+			},
+		},
+
+		question{
+			para{
+				"aaa",
+				"aa",
+			},
+			ans{
+				false,
+			},
+		},
+
+		question{
+			para{
+				"aa",
+				"*",
+			},
+			ans{
+				true,
+			},
+		},
+
+		question{
+			para{
+				"aa",
+				"a*",
+			},
+			ans{
+				true,
+			},
+		},
+
+		question{
+			para{
+				"ab",
+				"?*",
+			},
+			ans{
+				true,
+			},
+		},
+
+		question{
+			para{
+				"aab",
+				"c*a*b",
+			},
+			ans{
+				false,
+			},
+		},
+
+		question{
+			para{
+				"ab",
+				"*",
+			},
+			ans{
+				true,
+			},
+		},
+		// 如需多个测试，可以复制上方元素。
+	}
+
+	for _, q := range qs {
+		a, p := q.ans, q.para
+		fmt.Printf("~~%v~~\n", p)
+
+		ast.Equal(a.one, isMatch(p.s, p.p), "输入:%v", p)
+	}
+}

Algorithms/0058.length-of-last-word/README.md

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+# [58. Length of Last Word](https://leetcode.com/problems/length-of-last-word/)
+
+## 题目
+Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.
+
+If the last word does not exist, return 0.
+
+Note: A word is defined as a character sequence consists of non-space characters only.
+
+
+For example, 
+Given s = "Hello World",
+return 5.
+
+## 解题思路
+
+见程序注释

Algorithms/0058.length-of-last-word/length-of-last-word.go

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+package Problem0058
+
+func lengthOfLastWord(s string) int {
+
+}

Algorithms/0058.length-of-last-word/length-of-last-word_test.go

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+package Problem0058
+
+import (
+	"testing"
+	"fmt"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type question struct {
+	para
+	ans
+}
+
+// para 是参数
+type para struct {
+	s string
+}
+
+// ans 是答案
+type ans struct {
+	one  int 
+}
+
+func Test_Problem0058(t *testing.T) {
+	ast := assert.New(t)
+
+	qs := []question{
+
+		question{
+			para{
+					,
+			},
+			ans{
+					,
+			},
+		},
+	
+		// 如需多个测试，可以复制上方元素。
+	}
+
+	for _, q := range qs {
+		a, p := q.ans, q.para
+		fmt.Printf("~~%v~~\n", p)
+
+		ast.Equal(a.one, lengthOfLastWord(p.  ), "输入:%v", p)
+	}
+}