BZOJ3671 [Noi2014]随机数生成器

[Solution]

I thought of size-balanced tree at first, the got only 60 at the exams. In fact, we can just modify two arrays ml[i] and mr[i] meaning the left and the right pos that the number can be that row. Because there are many queries but few changes, it can get AC. What a pity that I didn't come up with that while examing.

[Code]

#define PROC "random"#include <cstdio>#include <cctype>#include <memory.h>#include <algorithm> using namespace std; int nextInt() {    int d, s = 0;    do        d = getchar();    while (!isdigit(d));    do        s = s * 10 + d - 48, d = getchar();    while (isdigit(d));    return s;} #define _l (long long int)#define mkword(a,b) (((a)<<16)|(b))#define hiword(a) ((a)>>16)#define loword(a) ((a)&65535) const int maxn = 5009;const int inf = 0x3f3f3f3f; int n, m, t, a[maxn][maxn], r[maxn * maxn], ans[maxn * 2], ml[maxn], mr[maxn]; void init() {    int x, a, b, c, d, q;    x = nextInt();    a = nextInt();    b = nextInt();    c = nextInt();    d = nextInt();    n = nextInt();    m = nextInt();    q = nextInt();    t = n * m;    for (int i = 1; i <= t; i ++)        r[i] = i;    for (int i = 1; i <= t; i ++) {        x = (_l a * (_l x * x % d) % d + _l b * x % d + c) % d;        swap(r[i], r[x % i + 1]);    }    for (int i = 0; i < q; i ++) {        int u = nextInt();        int v = nextInt();        swap(r[u], r[v]);    }    for (int i = 0; i < n; i ++)        for (int j = 0; j < m; j ++)            ::a[i][j] = r[i * m + j + 1];    for (int i = 0; i < n; i ++)        for (int j = 0; j < m; j ++)            r[::a[i][j]] = mkword(i + 1, j + 1);} void solve() {    for (int i = 1; i <= n; i ++)        ml[i] = 1, mr[i] = m;    for (int i = 0, p = 1; i < m + n - 1; i ++) {        while (ml[hiword(r[p])] > loword(r[p]) || mr[hiword(r[p])] < loword(r[p]))            p ++;        for (int j = 1; j < hiword(r[p]); j ++)            mr[j] = min(mr[j], loword(r[p]));        for (int j = hiword(r[p]) + 1; j <= n; j ++)            ml[j] = max(ml[j], loword(r[p]));        ans[i] = p ++;    }} int main() {#ifndef ONLINE_JUDGE    freopen("in.txt", "r", stdin);#endif     init();//  debugPrint();    solve();    for (int i = 0; i < (m + n - 1); i ++)        printf("%d%c", ans[i], ((i < (n + m - 2)) ? 32 : 10));//  putchar(10);    return 0;}