洛谷 #4113. 采花

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题意

问l~r区间中数量大于1的花的种类

题解

莫队

调试记录

cmp优化写炸

#include <cstdio>
#include <algorithm>
#include <cmath>
#define maxn 2000005

using namespace std;

struct node{
	int l, r, id;
}q[maxn];

int a[maxn], n, k, m, pos[maxn], cnt[maxn], ans[maxn];

inline bool cmp(node const &a, node const &b){ return (pos[a.l] == pos[b.l]) ? (pos[a.l] & 1) ? a.r < b.r : a.r > b.r : a.l < b.l; }
inline bool idcmp(node const &a, node const &b){ return a.id < b.id; }

inline int read(){
	int x = 0; char ch = getchar();
	while (ch < '0' || ch > '9') ch = getchar();
	while (ch >= '0' && ch <= '9') x = x * 10 + (ch & 15), ch = getchar();
	return x;
}

inline void solve(){
	int l = 1, r = 0, sum = 0;
	for (int i = 1; i <= m; i++){
		for (; r < q[i].r; r++) cnt[a[r + 1]]++, (cnt[a[r + 1]] == 2) ? sum++ : 0;
		for (; r > q[i].r; r--) (cnt[a[r]] == 2) ? sum-- : 0, cnt[a[r]]--;
		for (; l < q[i].l; l++) (cnt[a[l]] == 2) ? sum-- : 0, cnt[a[l]]--;
		for (; l > q[i].l; l--) cnt[a[l - 1]]++, (cnt[a[l - 1]] == 2) ? sum++ : 0;
		ans[q[i].id] = sum;
	}
}

inline void write(int x){
	if (x > 9) write(x / 10);
	putchar(x % 10 + '0');
}

int main(){
	n = read(), k = read(), m = read();
	
	for (int i = 1; i <= n; i++) a[i] = read();
	for (int i = 1; i <= m; i++) q[i].l = read(), q[i].r = read(), q[i].id = i;
	int block = sqrt(n);
	for (int i = 1; i <= m; i++) pos[i] = (i - 1) / block + 1;
	
	sort(q + 1, q + m + 1, cmp);
	solve();
//	sort(q + 1, q + m + 1, idcmp);
	
	for (int i = 1; i <= m; i++) write(ans[i]), putchar('\n');
	
	return 0;
}