-
Notifications
You must be signed in to change notification settings - Fork 2
/
392.判断子序列.html
89 lines (77 loc) · 2.55 KB
/
392.判断子序列.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>392. 判断子序列</title>
</head>
<body>
<script>
// https://leetcode-cn.com/problems/is-subsequence/
// 给定字符串 s 和 t ,判断 s 是否为 t 的子序列。
// 字符串的一个子序列是原始字符串删除一些(也可以不删除)字符而不改变剩余字符相对位置形成的新字符串。(例如,"ace"是"abcde"的一个子序列,而"aec"不是)。
// 进阶:
// 如果有大量输入的 S,称作 S1, S2, ... , Sk 其中 k >= 10亿,你需要依次检查它们是否为 T 的子序列。在这种情况下,你会怎样改变代码?
// 致谢:
// 特别感谢 @pbrother 添加此问题并且创建所有测试用例。
// 提示:
// 0 <= s.length <= 100
// 0 <= t.length <= 10^4
// 两个字符串都只由小写字符组成。
/**
* @param {string} s
* @param {string} t
* @return {boolean}
*/
var isSubsequence = function (s, t) {};
// --- answer-1 ---
// 双指针
var isSubsequence = function (s, t) {
let i = 0;
let j = 0;
while (j < t.length) {
if (s[i] === t[j]) {
i++;
j++;
} else {
j++;
}
}
return i === s.length;
};
// --- answer-1 ---
// --- answer-2 ---
// 动态规划
var isSubsequence = function (s = '', t = '') {
const [m, n] = [s.length, t.length];
const dp = Array.from({ length: m + 1 }, () => Array.from({ length: n + 1 }, () => 0));
for (let i = 1; i <= m; i++) {
for (let j = 1; j <= n; j++) {
// 更新dp[i][j],两种情况
if (s[i - 1] === t[j - 1]) {
dp[i][j] = dp[i - 1][j - 1] + 1;
} else {
dp[i][j] = dp[i][j - 1];
}
}
}
return dp[m][n] === m ? true : false;
};
// --- answer-2 ---
var s = 'abc',
t = 'ahbgdc';
var result = true;
var s = 'axc',
t = 'ahbgdc';
var result = false;
var s = 'b',
t = 'c';
var result = false;
console.log('s = ', s);
console.log('t = ', t);
console.log('result = ', result);
console.log('isSubsequence = ', isSubsequence(s, t));
</script>
</body>
</html>