VK Cup 2015 - Qualification Round 2 C. Name Quest

贪心，找t串中符合要求的最近最远的两个点。。。

#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 1000005
#define maxm 2000005
#define eps 1e-9
#define mod 1000000007
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid 
#define rson o<<1 | 1, mid+1, R
#define pii pair<int, int>
#pragma comment(linker, "/STACK:16777216")
typedef long long LL;
typedef unsigned long long ULL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
//head

char s[maxn];
char t[maxn];

void read()
{
	scanf("%s", s);
	scanf("%s", t);
}

void work()
{
	int lens = strlen(s);
	int lent = strlen(t);
	int ok = 0, ans1 = -1, ans2 = -1;
	for(int i = 0, j = 0; t[i] && !ok; i++) {
		if(s[j] == t[i]) j++;
		if(j == lens) ok = 1;
		if(ok) ans1 = i;
	}
	ok = 0;
	for(int i = lent-1, j = lens-1; i >= 0 && !ok; i--) {
		if(s[j] == t[i]) j--;
		if(j == -1) ok = 1;
		if(ok) ans2 = i;
	}
	if(ans1 == -1 || ans2 == -1 || ans1 >= ans2) printf("0\n");
	else printf("%d\n", ans2 - ans1);
}

int main()
{
	read();
	work();
	
	return 0;
}