Submission #240169

#	Time	Username	Problem	Language	Result	Execution time	Memory
240169		lyc	Mountains (IOI17_mountains)	C++14	100 / 100	44 ms	16384 KiB

mountains

#include "mountains.h"
#include <bits/stdc++.h>
using namespace std;

#define TRACE(x) cout << #x << " :: " << x << endl;
#define _ << " " <<
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(),(x).end()

const double EPS = 1e-6;
const int mxN = 2e3+5;
int memo[mxN][mxN];

int solve(int l, int r, vector<int>& y) {
    if (l > r) return 0;
    if (l == r) return 1;
    if (~memo[l][r]) return memo[l][r];
    int mx = l;
    FOR(i,l+1,r) if (y[i] > y[mx]) mx = i;
    memo[l][r] = solve(l,mx-1,y) + solve(mx+1,r,y);
    int cur = 1;
    if (l < mx-1) {
        int j = mx-2;
        double mng = (double)(y[mx]-y[mx-1]);
        RFOR(i,mx-2,l){
            double g = (double)(y[mx]-y[i])/(mx-i);
            if (g < mng+EPS) {
                mng = g;
                cur += solve(i+1,j,y);
                j = i-1;
            }
        }
        cur += solve(l,j,y);
    }
    if (mx+1 < r) {
        int j = mx+2;
        double mng = (double)(y[mx]-y[mx+1]);
        FOR(i,mx+2,r){
            double g = (double)(y[mx]-y[i])/(i-mx);
            if (g < mng+EPS) {
                mng = g;
                cur += solve(j,i-1,y);
                j = i+1;
            }
        }
        cur += solve(j,r,y);
    }
    memo[l][r] = max(memo[l][r],cur);
    return memo[l][r];
}

int maximum_deevs(vector<int> y) {
    memset(memo,-1,sizeof memo);
	return solve(0,SZ(y)-1,y);
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30