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离线处理+树状数组

//http://blog.csdn.net/zz_1215/
#pragma comment(linker, "/STACK:102400000,102400000")
#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<queue>
#include<stack>
#include<string>
#include<map>
#include<set>
#include<cmath>
#include<cassert>
#include<cstring>
#include<iomanip>
#include<ctime>
using namespace std;
typedef long long i64;
#define S64(a)          scanf(in64,&a)
#define SS(a)           scanf("%d",&a)
#define LL(a)           ((a)<<1)
#define RR(a)           (((a)<<1)+1)
#define pb              push_back
#define pf              push_front
#define X               first
#define Y               second
#define CL(Q)           while(!Q.empty())Q.pop()
#define MM(name,what)   memset(name,what,sizeof(name))
#define MC(a,b)		memcpy(a,b,sizeof(b))
#define MAX(a,b)        ((a)>(b)?(a):(b))
#define MIN(a,b)        ((a)<(b)?(a):(b))
#define read            freopen("in.txt","r",stdin)
#define write           freopen("out.txt","w",stdout)

const int inf = 0x3f3f3f3f;
const i64 inf64 = 0x3f3f3f3f3f3f3f3fLL;
const double oo = 10e9;
const double eps = 10e-9;
const double pi = acos(-1.0);
const int maxn = 100000 + 111;

struct zz{
	int l, r, id;
	bool operator < (const zz& cmp) const{
		return l < cmp.l;
	}
};

int n, m;
int a[maxn];
bool have[maxn];
int pos[maxn];
int ta[maxn];
int ans[maxn];
vector<zz>v;

int lowbit(int x){
	return x & (-x);
}

void add(int pos, int num, int ary[]){
	while (pos <= n){
		ary[pos] += num;
		pos += lowbit(pos);
	}
}

int sum(int x, int ary[]){   // 1 to x
	int ans = 0;
	while (x){
		ans += ary[x];
		x -= lowbit(x);
	}
	return ans;
}

int query(int x, int y){
	return sum(y, ta) - sum(x - 1, ta);
}

inline int find(int x){
	if (!have[x - 1] && !have[x + 1]){
		return 1;
	}
	else if (have[x - 1] && have[x + 1]){
		return -1;
	}
	else{
		return 0;
	}
}

void start(){
	for (int i = 1; i <= n; i++){
		have[i] = false;
		ta[i] = 0;
	}
	for (int i = 1; i <= n; i++){
		pos[a[i]] = i;
	}
	for (int i = 1; i <= n; i++){
		add(i, find(a[i]), ta);
		have[a[i]] = true;
	}
	int temp = 0;
	for (int i = 1; i <= n; i++){
		while (temp <(int) v.size()){
			if (v[temp].l == i){
				ans[v[temp].id] = query(v[temp].l, v[temp].r);
				temp++;
			}
			else{
				break;
			}
		}
		have[a[i]] = false;
		if (have[a[i] + 1]){
			add(pos[a[i] + 1], 1, ta);
		}
		if (have[a[i] - 1]){
			add(pos[a[i] - 1], 1, ta);
		}
	}
	return;
}

int main()
{
	int T;
	cin >> T;
	while (T--){
		cin >> n >> m;
		for (int i = 1; i <= n; i++){
			cin >> a[i];
		}
		zz temp;
		v.clear();
		for (int i = 1; i <= m; i++){
			//cin >> temp.l >> temp.r;
			SS(temp.l); SS(temp.r);
			temp.id = i;
			v.push_back(temp);
		}
		sort(v.begin(), v.end());
		start();
		for (int i = 1; i <= m; i++){
			//cout << ans[i] << endl;
			printf("%d\n", ans[i]);
		}
	}
	return 0;
}

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hdu 4638 Group

标签：blog   http   os   io   for   art   ar   cti   

原文地址：http://blog.csdn.net/zz_1215/article/details/38421269