Submission #961641

#	Time	Username	Problem	Language	Result	Execution time	Memory
961641		BhavayGoyal	Growing Vegetable is Fun 3 (JOI19_ho_t3)	C++14	100 / 100	261 ms	134636 KiB

joi2019_ho_t3

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

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<class T> using oset = 
            tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define ll long long
#define ld long double
#define ar array
#define vi vector<int>
#define vii vector<vector<int>>
#define pii pair<int, int>
#define pb push_back
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define endl "\n"

const int MOD = 1e9+7;
const int inf = 1e9;
const ll linf = 1e18;

const int d4i[4]={-1, 0, 1, 0}, d4j[4]={0, 1, 0, -1};
const int d8i[8]={-1, -1, 0, 1, 1, 1, 0, -1}, d8j[8]={0, 1, 1, 1, 0, -1, -1, -1};

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());


// -------------------------------------------------- Main Code --------------------------------------------------

/*
YRGGRRGGYY

dp[i][red][green][yellow][prevCol] = dp[i+1][]

RYRGY
*/

const int N = 401;
int n, arr[N], countPrev[4][N], r = 0, g = 0, y = 0;;
vector<vector<vii>> dp;
vi pos[4];

int sol(int red, int green, int yellow, int prev) {
    int idx = (red+green+yellow+1);
    if (idx == n+1) return 0;
    if (red > r || green > g || yellow > y) return inf;
    
    if (dp[red][green][yellow][prev] != -1) return dp[red][green][yellow][prev];
    int ans = inf;
    for (int j = 1; j <= 3; j++) {
        if (j == prev) continue;
        int cost = inf;
        if (j == 1) {
            red++;
            if (red-1 < pos[j].size()) {
                int p = pos[j][red-1];
                cost = max(0, countPrev[2][p] -  green) + max(0, countPrev[3][p] -  yellow);
            }
        }
        if (j == 2) {
            green++;
            if (green-1 < pos[j].size()) {
                int p = pos[j][green-1];
                cost = max(0, countPrev[1][p] -  red) + max(0, countPrev[3][p] -  yellow);                
            }
        } 
        if (j == 3) {
            yellow++;
            if (yellow-1 < pos[j].size()) {
                int p = pos[j][yellow-1];
                cost = max(0, countPrev[2][p] -  green) + max(0, countPrev[1][p] -  red);
            }
        }
        ans = min(ans, sol(red, green, yellow, j) + cost);
        if (j == 1) red--; if (j == 2) green--; if (j == 3) yellow--;
    }
    return dp[red][green][yellow][prev] = ans;
}

void sol() {
    cin >> n;
    string s; cin >> s;
    for (int i = 0; i < n; i++) {
        if (s[i] == 'R') arr[i+1] = 1, r++;
        if (s[i] == 'G') arr[i+1] = 2, g++;
        if (s[i] == 'Y') arr[i+1] = 3, y++;
        pos[arr[i+1]].pb(i+1);
        countPrev[arr[i+1]][i+1] = 1;
    }

    dp = vector<vector<vii>>(r+1, vector<vii>(g+1, vii(y+1, vi(4, -1))));

    for (int j = 1; j <= 3; j++) {
        for (int i = 1; i <= n; i++) {
            countPrev[j][i] += countPrev[j][i-1];
        }
    }

    int ans = sol(0, 0, 0, 0);
    cout << (ans==inf?-1:ans) << endl;
}

int main () {
    auto begin = std::chrono::high_resolution_clock::now();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;    
    // cin >> t;
    for(int i = 1; i <= t; i++) 
    {
        sol();
    }
    auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
    return 0;
}

Compilation message (stderr)

joi2019_ho_t3.cpp: In function 'int sol(int, int, int, int)':
joi2019_ho_t3.cpp:60:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |             if (red-1 < pos[j].size()) {
      |                 ~~~~~~^~~~~~~~~~~~~~~
joi2019_ho_t3.cpp:67:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |             if (green-1 < pos[j].size()) {
      |                 ~~~~~~~~^~~~~~~~~~~~~~~
joi2019_ho_t3.cpp:74:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |             if (yellow-1 < pos[j].size()) {
      |                 ~~~~~~~~~^~~~~~~~~~~~~~~
joi2019_ho_t3.cpp:80:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   80 |         if (j == 1) red--; if (j == 2) green--; if (j == 3) yellow--;
      |         ^~
joi2019_ho_t3.cpp:80:28: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   80 |         if (j == 1) red--; if (j == 2) green--; if (j == 3) yellow--;
      |                            ^~

• Subtask 1: 5 / 5
• Subtask 2: 55 / 55
• Subtask 3: 15 / 15
• Subtask 4: 25 / 25