Problem:
Score : 500 points

Problem Statement

Given are two strings s and t consisting of lowercase English letters. Determine if there exists an integer i satisfying the following condition, and find the minimum such i if it exists.

Let s' be the concatenation of 10^{100} copies of s. t is a subsequence of the string {s'}_1{s'}_2\ldots{s'}_i (the first i characters in s').

Notes

A subsequence of a string a is a string obtained by deleting zero or more characters from a and concatenating the remaining characters without changing the relative order. For example, the subsequences of contest include net, c, and contest.

Constraints

1 \leq |s| \leq 10^5

1 \leq |t| \leq 10^5

s and t consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

s
t

Output

If there exists an integer i satisfying the following condition, print the minimum such i; otherwise, print -1.

Sample Input 1

contest
son

Sample Output 1

10

t = son is a subsequence of the string contestcon (the first 10 characters in s' = contestcontestcontest...), so i = 10 satisfies the condition.

On the other hand, t is not a subsequence of the string contestco (the first 9 characters in s'), so i = 9 does not satisfy the condition.

Similarly, any integer less than 9 does not satisfy the condition, either. Thus, the minimum integer i satisfying the condition is 10.

Sample Input 2

contest
programming

Sample Output 2

-1

t = programming is not a substring of s' = contestcontestcontest.... Thus, there is no integer i satisfying the condition.

Sample Input 3

contest
sentence

Sample Output 3

33

Note that the answer may not fit into a 32-bit integer type, though we cannot put such a case here.

Solution in JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function Main(input) {
	var s = input.split("\n")[0];
  var t = input.split("\n")[1];
  //初手の終了条件
  //sの文字の種類に対してtの文字の種類が多い
  //または
  //tで出てくる文字の種類が1つ以上異なる
  var sUsed = s.split("").sort();
  var tUsed = t.split("").sort();
  sUsed = sUsed.filter(function (x, i, self) {
            return self.indexOf(x) === i;
        });
  
  tUsed = tUsed.filter(function (x, i, self) {
            return self.indexOf(x) === i;
        });
  if(tUsed.length > sUsed.length){
     console.log("-1");
    return;
  }else{
    for(var i = 0; i < tUsed.length; i++){
      if(sUsed.indexOf(tUsed[i]) == -1){
         console.log("-1");
         return;
      }
    }
  }
  var tList = t.split("");
  var count = 1;
  var output = 0;
  var sKurikaesi = 0;//whileループするたび+1
  while(tList.length != 0){
    var sTmp = s;
    var sTmp2 = s;
    while(sTmp2.indexOf(tList[0]) != -1){
      output = (sKurikaesi * s.length) + sTmp.indexOf(tList[0]) + 1;
      sTmp = sTmp.slice(0,s.indexOf(tList[0])) + "?" + sTmp.slice(s.indexOf(tList[0]) + 1,s.length);
      var nextPosi = s.indexOf(tList[0]);
      tList.shift();
      sTmp2 = sTmp.slice(nextPosi+1,sTmp.length);
      //console.log("output:" + sTmp);
      //console.log("tmp2" + sTmp2)
      //console.log(tList);
      //console.log(output);
      if(tList.length == 0){
        break;
      }
    }
    if(tList.length == 0){
      //console.log("通貨？");
        break;
    }
      sKurikaesi++;
    
  }
  console.log(output);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));