HDu 5475 An easy problem(セグメントツリー)

タイトルリンク:hdu 5475 An easy problem

問題を解く構想.

単一点修正.直接暴力でもできるようで、データが弱い.

コード#コード#

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
const int maxn = 1e5 + 5;
#define lson(x) ((x)<<1)
#define rson(x) (((x)<<1)|1)

int N, mod, P[maxn];
int lc[maxn<<2], rc[maxn<<2], s[maxn<<2];

void pushup(int u) {
    s[u] = 1LL * s[lson(u)] * s[rson(u)] % mod;
}

void build (int u, int l, int r) {
    lc[u] = l, rc[u] = r, s[u] = 1;

    if (l == r) return;
    int mid = (l + r) >> 1;
    build (lson(u), l, mid);
    build (rson(u), mid+1, r);
    pushup(u);
}

void modify(int u, int x, int v) {
    if (lc[u] == x && rc[u] == x) {
        s[u] = v % mod;
        return;
    }

    int mid = (lc[u] + rc[u]) >> 1;
    if (x <= mid) modify(lson(u), x, v);
    else modify(rson(u), x, v);
    pushup(u);
}

int main () {
    int cas, t;
    scanf("%d", &cas);
    for (int kcas = 1; kcas <= cas; kcas++) {
        scanf("%d%d", &N, &mod);
        build(1, 1, N);
        printf("Case #%d:
", kcas);
        for (int i = 1; i <= N; i++) {
            scanf("%d%d", &t, &P[i]);
            if (t == 1) modify(1, i, P[i]);
            else modify(1, P[i],  1);
            printf("%d
", s[1]);
        }
    }
    return 0;
}