Codeforces 85D Sum of Medians(線段樹)

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85D Sum of Medians

題目連結

題意：一個集合有添加，刪除元素，每次查詢輸出集合位置為i % 5 == 3的位置和

思路：線段樹，線段樹記錄下% 5 == 0, 1, 2, 3, 4的和，並且記錄一個mov表示右移多少，每次添加一個值的時候，就當前位置之後的一整段位置都要右移一個單位，這樣去搞線段樹維護一下即可

代碼：

#include <cstdio>#include <cstring>#include <cstdlib>#include <algorithm>using namespace std;const int N = 100005;typedef long long ll;int n;char str[10];int op[N], opx[N];struct Hash {int val, rank, id;} hash[N];int hn;bool cmp(Hash a, Hash b) {return a.val < b.val;}#define lson(x) ((x<<1)+1)#define rson(x) ((x<<1)+2)struct Node {int l, r, mov; ll k[5];} node[N * 4];void pushup(int x) {if (node[x].l == node[x].r) {ll tmp = 0;for (int i = 0; i < 5; i++) if (node[x].k[i]) tmp = node[x].k[i];if (tmp == 0) return;memset(node[x].k, 0, sizeof(node[x].k));node[x].k[node[x].mov % 5] = tmp;return; }for (int i = 0; i < 5; i++)node[x].k[(i + node[x].mov) % 5] = node[lson(x)].k[i] + node[rson(x)].k[i];}void build(int l, int r, int x = 0) {node[x].l = l; node[x].r = r;node[x].mov = 0;memset(node[x].k, 0, sizeof(node[x].k));if (l == r) return;int mid = (l + r) / 2;build(l, mid, lson(x));build(mid + 1, r, rson(x));}void add(int l, int r, int v, int x = 0) {if (node[x].l >= l && node[x].r <= r) {node[x].mov += v;pushup(x);return; } int mid = (node[x].l + node[x].r) / 2; if (l <= mid) add(l, r, v, lson(x)); if (r > mid) add(l, r, v, rson(x)); pushup(x);}int to[N];void add2(int v, int val, int x = 0) {if (node[x].l == node[x].r) { memset(node[x].k, 0, sizeof(node[x].k));if (val == 1)  node[x].k[node[x].mov % 5] = to[node[x].l];return; }int mid = (node[x].l + node[x].r) / 2;if (v <= mid) add2(v, val, lson(x));if (v > mid) add2(v, val, rson(x));pushup(x);}int main() {hn = 0;scanf("%d", &n); for (int i = 0; i < n; i++) { scanf("%s", str); if (str[0] == 'a' || str[0] == 'd') {   op[i] = 1;   if (str[0] == 'd') op[i] = -1;   scanf("%d", &opx[i]);   hash[hn].id = i;   hash[hn++].val = opx[i];} else op[i] = 0; } sort(hash, hash + hn, cmp); to[0] = hash[0].val; hash[0].rank = 0; for (int i = 1; i < hn; i++) { hash[i].rank = hash[i - 1].rank; if (hash[i].val != hash[i - 1].val) {    hash[i].rank++;    to[hash[i].rank] = hash[i].val;}  }  build(0, hash[hn - 1].rank);  for (int i = 0; i < hn; i++)  opx[hash[i].id] = hash[i].rank;for (int i = 0; i < n; i++) {if (op[i] == 0) printf("%lld\n", node[0].k[3]);else {  add(opx[i], hash[hn - 1].rank, op[i]);     add2(opx[i], op[i]);} }return 0;}

Codeforces 85D Sum of Medians(線段樹)