JavaScriptAlgorithms/Classical algorithm problem/KMP.html at master · biaodigit/JavaScriptAlgorithms · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>KMP</title>
</head>
<body>
<script>
    function calNext(str, len, next) {
        let j = -1;
        next[0] = -1;
        for (let i = 1; i < len; i++) {
            while (j > -1 && str[j + 1] !== str[i]) {
                j = next[j]
            }
            if (str[i] === str[j + 1]) {
                j++
            }
            next[i] = j
        }
    }

    function kmp(str, pstr) {
        let slen = str.length,
            plen = pstr.length,
            j = -1,
            next = new Array(plen),
            res = [];
        calNext(pstr, plen, next);
        for (let i = 0; i < slen; i++) {
            while (j > -1 && str[i] !== pstr[j + 1]) {
                j = next[j]
            }
            if (str[i] === pstr[j + 1]) {
                j++
            }
            if (j === plen - 1) {
                res.push(i - j);
                j = -1
            }
        }
        return res.length ? res : 0
    }

    console.log(kmp("bbc abcdab abcdababacde", "ababac"))
</script>
</body>
</html>