hdu 6129(找规律lucas)

Posted 2020-10-03

把初始a的每一个元素对m次变换的贡献写出来，发现是一个斜着的杨辉三角，根据lucas，当且仅当a&b == b，C(a, b)为奇数，又因为&和^运算极快，4e10的复杂度也就跑了一秒。

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <string>
#include <cmath>
#include <map>
using namespace std;
const int maxn = 200005;
int a[maxn], b[maxn];
int solve(int x, int y)
{
//    cout << "x == " << x << " y == " << y << endl;
    if(x == 1)
        return a[y];
    if(y == 1)
        return a[1];
    int tmp = min(x, y);
    for(int i = 30; i >= 0; --i)
        if(tmp - (1 << i) > 0)
        {
            return solve(x - (1 << i), y) ^ solve(x, y - (1 << i));
        }
}
int main()
{
//    freopen("1010.in", "r", stdin);
    int T;
    scanf("%d", &T);
    while(T--)
    {
        int n, m;
        scanf("%d%d", &n, &m);
        for(int i = 1; i <= n; ++i)
        {
            scanf("%d", &a[i]);
        }
        memset(b, 0, sizeof(b));
        for(int i = 0; i <= n - 1; ++i)
        {
            int y = m + i - 1, x = i;
//            cout << "x == " << x << " y == " << y << endl;
            if((x & y) == x)
            {
                for(int j = 1; j + i <= n; ++j)
                    b[j + i] ^= a[j];
            }
        }
        for(int i = 1; i <= n; ++i)
        {
            if(i != 1)
                printf(" ");
            printf("%d", b[i]);
        }
        printf("\n");
    }
}

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