HDOJ 1711 Number Sequence

最新推荐文章于 2019-07-31 15:00:04 发布

luminous11

最新推荐文章于 2019-07-31 15:00:04 发布

阅读量392

点赞数

CC 4.0 BY-SA版权

分类专栏： HDOJ KMP&&EXKMP

本文链接：https://blog.youkuaiyun.com/luminous11/article/details/44870973

HDOJ 同时被 2 个专栏收录

116 篇文章

订阅专栏

KMP&&EXKMP

2 篇文章

订阅专栏

本文介绍了一种高效的字符串匹配算法——KMP算法，并提供了详细的实现步骤和AC代码示例。通过预处理模式串来提高匹配效率，适用于需要频繁进行字符串搜索的场景。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

题意：给出一个模式串和一个主串，找出模式串在主串中第一次匹配的位置，不存在匹配时输出-1

链接：http://acm.hdu.edu.cn/showproblem.php?pid=1711

思路：KMP，当有匹配时输出起点位置即可

注意点：无

以下为AC代码：

Run ID	Submit Time	Judge Status	Pro.ID	Exe.Time	Exe.Memory	Code Len.	Language	Author
13036442	2015-03-05 19:40:56	Accepted	1711	1248MS	12912K	2616 B	G++	luminous11

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <string>
#include <vector>
#include <deque>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <cctype>
#include <climits>
#include <iomanip>
#include <cstdlib>
#include <algorithm>
//#include <unordered_map>
//#include <unordered_set>
#define ll long long
#define ull unsigned long long
#define all(x) (x).begin(), (x).end()
#define clr(a, v) memset( a , v , sizeof(a) )
#define pb push_back
#define RDI(a) scanf ( "%d", &a )
#define RDII(a, b) scanf ( "%d%d", &a, &b )
#define RDIII(a, b, c) scanf ( "%d%d%d", &a, &b, &c )
#define RDS(s) scanf ( "%s", s )
#define PIL(a) printf ( "%d\n", a )
#define PIIL(a,b) printf ( "%d %d\n", a, b )
#define PIIL(a,b,c) printf ( "%d %d %d\n", a, b, c )
#define PSL(s) printf ( "%s\n", s )
#define REP(i,m,n) for ( int i = m; i <= n; i ++ )
#define DEP(i,m,n) for ( int i = m; i >= n; i -- )
#define REPI(i,m,n,k) for ( int i = m; i <= n; i += k )
#define DEPI(i,m,n,k) for ( int i = m; i >= n; i -= k )
#define READ(f) freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)
using namespace std;
const double pi = acos(-1);
const double eps = 1e-10;
const int dir[4][2] = { 1,0, -1,0, 0,1, 0,-1 };
struct node{
    int x, y, cnt;
    node(){}
    node( int _x, int _y ) : x(_x), y(_y) {}
    node( int _x, int _y, int _cnt ) : x(_x), y(_y), cnt(_cnt) {}
};
int pre[1000010];
int x[1000010];
int y[1000010];
void preKMP ( int x[], int m )
{
    int i, j;
    j = pre[0] = -1;
    i = 0;
    while ( i < m ){
        while ( j != -1 && x[i] != x[j] ) j = pre[j];
        pre[++i] = ++j;
        //if ( x[++i] == x[++j] ) pre[i] = pre[j];
        //else pre[i] = j;
    }
}

int kmp ( int x[], int m, int y[], int n )
{
    int i, j;
    int ans = 0;
    preKMP ( x, m );
    i = j = 0;
    while ( i < n ){
        while ( j != -1 && x[j] != y[i] ) j = pre[j];
        //cout << x[j] << ' ' << y[i] << ' ' << i << ' ' << j << endl;
        i ++;
        j ++;
        if ( j >= m ){
            return i - j + 1;
        }
    }
    return -1;
}
int main()
{
    int T;
    RDI ( T );
    while ( T -- ){
        int m, n;
        clr ( pre, 0 );
        clr ( x, 0 );
        clr ( y, 0 );
        RDII ( n, m );
        REP ( i, 0, n - 1 ) RDI ( x[i] );
        REP ( i, 0, m - 1 ) RDI ( y[i] );
        PIL ( kmp ( y, m, x, n ) );
    }
    return 0;
}