POJ - 2100 Graveyard Design

题目大意:

给定一个t,求一段连续数的平方和(例如:x1*x1+x2*x2+x3*x3)等于t的方法有几种,并要求输出方案

  

分析:

尺取法。应为连续的数时单调的,所以能使用尺取法。个人是尺取时看sum==t,是就记录下l,r,并将其存
放到vector里,则size()就是方案书,l-r就是方案里包含几个数,[l,r)区间内数就是方案。

  

code:

#define debug
//#define opentext
#include<stdio.h>
#include<math.h>
#include<cmath>
#include<queue>
#include<stack>
#include<string>
#include<cstring>
#include<string.h>
#include<algorithm>
#include<iostream>
#include<vector>
#include<functional>
#include<iomanip>
#include<map>
#include<set>
#define pb push_back
#define dbg(x) cout<<#x<<" = "<<(x)<<endl;
#define lson l,m,rt<<1
#define cmm(x) cout<<"("<<(x)<<")";
#define rson m+1,r,rt<<1|1
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll>PLL;
typedef pair<int,ll>Pil;
typedef pair<ll,int>Pli;
const ll INF = 0x3f3f3f3f;
const ll inf=0x7fffffff;
const double eps=1e-8;
const int maxn =1000000;
const int N = 510;
const ll mod=1e9+7;
const ll MOD=10007;
//------
//define
ll s[maxn];
const int n=1e7;
struct node {
	int l,r;
	node(int l,int r):r(r),l(l) {}
};
vector<node>m;
//solve
void solve() {
	ll t;
	while(cin>>t) {
		ll sum=0;
		int l=1,r=1,cnt=0;
		for(;;) {
			while(r*r<=t&&sum<t) {//r*r>t时不管怎么取都是不可能组成t的 
				sum+=(1ll*r*r);
				r++;
			}
			if(sum==t) {
				m.push_back(node(l,r));
			}
			sum-=(1ll*l*l);
			l++;
			if(sum<=0)break;
		}
		cout<<m.size()<<endl;
		for(int i=0; i<m.size(); i++) {
			int l=m[i].l,r=m[i].r;
			cout<<r-l;
			for(int j=l; j<r; j++)cout<<" "<<j;
			cout<<endl;
		}
		m.clear();
	}
}
int main() {
	ios_base::sync_with_stdio(false);
//-----------freopen-------------------
#ifdef debug
	freopen("in.txt", "r", stdin);
#ifdef opentext
	freopen("out.txt","w",stdout);
#endif
#endif
//-------------------------------------
	cin.tie(0);
	cout.tie(0);
	solve();
//-----------opentext------------------
#ifdef opentext
	fclose(stdin);
	fclose(stdout);
	system("out.txt");
#endif
//-------------------------------------
	return 0;
}

  

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转载自www.cnblogs.com/visualVK/p/9178703.html