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 C (Clang 3.8.0) (judge verdict: Wrong Answer)

#include<stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void) {
	char s[100000];//100000
	char t[100000];
	scanf("%s", s);
	scanf("%s",t);
	//printf("%s %s\n", s, t);
	int n = strlen(s);
	int nt = strlen(t);
	//printf("%d %d\n", n, nt);
	long c = 0;
	long cc = 0;
	int f = 0;
	for (;;) {
		if (f == 1) break;
		int tmp = c;
		for (int i = 0; i < n; i++) {
			cc++;
			if (t[c] == s[i]) {
				//printf("%c %c\n", &t[c], &s[i]);
				c++;
				if (c == nt) {
					printf("%ld", cc);
					f = 1;
					break;
				}
			}
		}
		if (c == tmp) {
			break;
		}
	}
	if (f == 0) {
		printf("-1");
	}
}