poj 3274

hash的算法倒是没神马收获，倒是感觉这两天看clean code很管用，调试代码的时间大幅度下降了。

错啊，要是hash函数写的好的话，会快很多的。

附更快版本的hash函数，简单的修改即可。

int hashval(int pos) {
    int res = 0;
    for (int i = 1; i < k; i++) {
        res = (res + dp[pos][i] + maxarray - dp[pos][0]) % maxarray;
    }
    return res;
}

#include <iostream>
#include <string>
#include <vector>
#include <cstdlib>
#include <cmath>
#include <map>
#include <algorithm>
#include <list>
#include <ctime>
#include <set>
#include <string.h>
#include <queue>
#include <cstdio>
using namespace std;
#define CLR(arr, what) memset(arr, what, sizeof(arr))
int n, k;
const int maxarray = 100001;
int dp[maxarray][32];
vector<int> dic[maxarray];
void save(int pos, int num) {
    if (0 == pos) {
        for (int a = 0; a < k; a++) {
            if (num & (1 << a)) {
                dp[pos][a] = 1;
            }
        }
    } else {
        for (int a = 0; a < k; a++) {
            if (num & (1 << a)) {
                dp[pos][a] = dp[pos - 1][a] + 1;
            } else {
                dp[pos][a] = dp[pos - 1][a];
            }
        }

    }
}
int hashval(int pos) {
    int res = 0;
    for (int i = 1; i < k; i++) {
        res = (res + dp[pos][i] + maxarray - dp[pos][i - 1]) % maxarray;
    }
    return res;
}
bool check(int pos1, int pos2, int res) {
    bool judge = true;
    if (pos2 - pos1 <= res) {
        return false;
    }
    int diff = dp[pos1][0] - dp[pos2][0];
    for (int i = 1; i < k; i++) {
        judge = judge && ((dp[pos1][i] - dp[pos2][i]) == diff);
        if (!judge) {
            return false;
        }
    }
    return true;
}
int maxedge(vector<int> var, int res) {
    int sz = var.size();
    bool judge;
    for (int i = 0; i < sz; i++) {
        for (int j = i + 1; j < sz; j++) {
            judge = check(var[i], var[j], res);
            if (judge) {
                res = max(res, var[j] - var[i]);
            }
        }
    }
    return res;
}
int maxedgestart(int res) {
    bool judge;
    for (int i = res; i < n; i++) {
        judge = true;
        for (int j = 1; j < k; j++) {
            if (dp[i][j] != dp[i][j - 1]) {
                judge = false;
                break;
            }
        }
        if (judge) {
            res = i + 1;
        }
    }
    return res;
}
int main() {
    int tmp;
    cin >> n >> k;
    for (int i = 0; i < n; i++) {
        scanf("%d", &tmp);
        save(i, tmp);
    }
    int curhash;
    for (int i = 0; i < n; i++) {
        curhash = hashval(i);
        dic[curhash].push_back(i);
    }
    int res = 0;
    res= max(res, maxedgestart(res));
    for (int i = 0; i < maxarray; i++) {
        res = max(res, maxedge(dic[i], res));
    }
    cout << res << endl;
    return 0;
}

from kakamilan