POJ1635【树的同构】【hash】

最新推荐文章于 2020-06-06 17:24:03 发布

原创最新推荐文章于 2020-06-06 17:24:03 发布 · 544 阅读

0 ·

CC 4.0 BY-SA版权

图论专栏收录该内容

20 篇文章

订阅专栏

本文介绍了一种基于字符串相似性比较的算法实现，通过构建特定的数据结构并利用哈希技术来快速判断两个字符串是否相同。文章详细展示了算法的实现过程，包括节点插入、回溯操作及哈希值计算等关键步骤。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

/* I will wait for you*/

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <string>
#define make make_pair
#define fi first
#define se second

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;

const int maxn = 10010;
const int maxm = 1010;
const int maxs = 26;
const int inf = 0x3f3f3f3f;
const int P = 19001;
const double error = 1e-9;

inline int read()
{
	int x = 0, f = 1;
	char ch = getchar();
	while (ch <= 47 || ch >= 58)
		f = (ch == 45 ? -1 : 1), ch = getchar();
	while (ch >= 48 && ch <= 57)
		x = x * 10 + ch - 48, ch = getchar();
	return x * f;
}

char s[maxn], t[maxn];

struct edge
{
	int v, next;
} e[maxn];

int T, cnt, sum, head[maxn], ran[maxn], fa[maxn];

int rand_a, rand_b, rand_p;

void insert(int u, int v)
{
	e[cnt] = (edge) {v, head[u]}, head[u] = cnt++;
}

int dfs(int u)
{
	int hash = rand_a;

	vector<int> h;

	for (int i = head[u]; i != -1; i = e[i].next)
		h.push_back(dfs(e[i].v));
	sort(h.begin(), h.end());

	for (int i = 0; i < h.size(); i++)
		hash = ((hash * rand_p ) ^ h[i]) % P;
	
	return hash * rand_b % P;
}

void init()
{
	rand_a = rand() % 19000 + 1;
	rand_b = rand() % 19000 + 1;
	rand_p = rand() % 19000 + 1;
}

int solve(char* s)
{
	int n = strlen(s), t = 1;

	cnt = 0, sum = 1;
	memset(head, -1, sizeof head);

	for (int i = 0; i < n; i++) {
		if (s[i] == '0') {
			insert(t, ++sum);
			fa[sum] = t, t = sum;
		}
		if (s[i] == '1')
			t = fa[t];
	}

	return dfs(1);
}

int main()
{
	T = read(), init();

	while (T--) {
		scanf("%s%s", s, t);
		int fs = solve(s);
		int ft = solve(t);

		if (fs == ft)
			printf("same\n");
		else
			printf("different\n");
	}

	return 0;
}