Submission #1367052

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Source Code Expand

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
typedef long long ll ;
#define rep(i, a, b) for (int i = a; i <= b; ++ i) 
const int N = 1000005 ;
using namespace std ;

int n, h[26], f[N][26], r[N] ;
char s[N], t[N] ;
struct poi {
    int x, y ;
} a[N] ;

int main() {
    scanf("%d", &n) ;
    scanf("%s%s", s + 1, t + 1) ;
    bool flg = true ;
    rep(i, 1, n) if (s[i] != t[i]) 
        flg = false ;
    if (flg) {
        printf("0\n") ;
        return 0 ;
    }
    rep(i, 0, 25) h[i] = 0 ;
    rep(i, 1, n) {
        h[s[i] - 'a'] = i ;
        rep(j, 0, 25) f[i][j] = h[j] ;
    }
    int las = n ;
    for (int i = n ; i; -- i) {
        las = min(las, i) ;
        int x = f[las][t[i] - 'a'] ;
        if (!x) {
            printf("-1\n") ;
            return 0 ; 
        }
        r[x] = max(r[x], i) ;
        las = x ;
    }
    int tot = 0, ans = 0 ;
    rep(i, 1, n) if (r[i]) {
        ++ tot ;
        a[tot].x = i, a[tot].y = r[i] ;
    }
    a[tot + 1].x = n + 1 ;
    rep(i, 1, n) {
        int l = i, r = tot + 1, goal = a[i].y - i, ret = r ;
        for ( ; l <= r ; ) {
            int mid = (l + r) / 2 ;
            if (a[mid].x - mid >= goal) ret = mid, r = mid - 1 ;
                else l = mid + 1 ;
        }
        ans = max(ans, ret - i) ;
    }
    printf("%d\n", ans) ;
    return 0 ;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:18:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n) ;
                     ^
./Main.cpp:19:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s%s", s + 1, t + 1) ;
                                 ^

Judge Result