Algorithm to find the minimum length of substring having all characters of other string

Question

I have a two strings:
string1 - hello how are you,
String2 - olo (including space character)

Output: lo ho ( hello

Answer 1

This is a example of implementation with JavaScript. The logic is similar as @Aprillion wrote above.

DEMO : http://jsfiddle.net/ZB6vm/4/

var s1 = "hello how are you";
var s2 = "olo";
var left, right;
var min_distance;
var answer = "";

// make permutation recursively
function permutate(ar, arrs, k) {
    // check if the end of recursive call
    if (k == arrs.length) {
        var r = Math.max.apply(Math, ar);
        var l = Math.min.apply(Math, ar);
        var dist = r - l + 1;
        if (dist <= min_distance) {
            min_distance = dist;
            left = l;
            right = r;
        }
        return;
    }
    for (var i in arrs[k]) {
        var v = arrs[k][i];
        if ($.inArray(v, ar) < 0) {
            var ar2 = ar.slice();
            ar2.push(v);
             // recursive call
            permutate(ar2, arrs, k + 1);
        }
    }
}

function solve() {
    var ar = [];   // 1-demension array to store character position
    var arrs = []; // 2-demension array to store character position
    for (var i = 0; i < s2.length; i++) {
        arrs[i] = [];
        var c = s2.charAt(i);
        for (var k = 0; k < s1.length; k++) { // loop by s1
            if (s1.charAt(k) == c) {
                if ($.inArray(k, arrs[i]) < 0) {
                    arrs[i].push(k); // save position found
                }
            }
        }
    }
    // call permutate
    permutate(ar, arrs, 0);
    answer = s1.substring(left, right + 1);
    alert(answer);
}

solve();

Hope this helps.