Submission #1088535

#	Time	Username	Problem	Language	Result	Execution time	Memory
1088535		efishel	Growing Vegetable is Fun 3 (JOI19_ho_t3)	C++17	60 / 100	22 ms	54572 KiB

joi2019_ho_t3

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector <ll>;
using vi = vector <int>;

vi ou[3];
bool vis[403][403][403][3];
int dp[403][403][403][3]; // dp[a][b][c][last] = min operations to have a valid string\
rn having a prefix of length a+b+c having taken a as, b bs, and c cs, having the last color as last
bool vis2[403][403][403][3];
unsigned char dp2[403][403][403][3];

unsigned char fcost (int a, int b, int c, int wh) { // calculates the followisg sum:
/*
    for (ll j = 0; j < a; j++) if (ou[0][j] < ou[wh][t]) ans++;
    for (ll j = 0; j < b; j++) if (ou[1][j] < ou[wh][t]) ans++;
    for (ll j = 0; j < c; j++) if (ou[2][j] < ou[wh][t]) ans++;
*/
    if (vis2[a][b][c][wh]) return dp2[a][b][c][wh];
    vis2[a][b][c][wh] = true;
    int t = wh == 0 ? a : wh == 1 ? b : c;
    if ((a ? ou[0][a-1] : -1) >= ou[wh][t]) return dp2[a][b][c][wh] = fcost(a-1, b, c, wh);
    if ((b ? ou[1][b-1] : -1) >= ou[wh][t]) return dp2[a][b][c][wh] = fcost(a, b-1, c, wh);
    if ((c ? ou[2][c-1] : -1) >= ou[wh][t]) return dp2[a][b][c][wh] = fcost(a, b, c-1, wh);
    return dp2[a][b][c][wh] = a+b+c;
}

ll n;
int bey[3]; // bey[i] = how many taken are beyond the last taken of color i
int ptr[3][3];
// bool taken[403];
int solve (ll a, ll b, ll c, ll last) { // have taken the first a as b bs and c cs, the last rn is last
    if (a+b+c == n) return 0;
    if (vis[a][b][c][last]) return dp[a][b][c][last];
    vis[a][b][c][last] = true;
    int &ans = dp[a][b][c][last];
    ans = 1e9;
    int i = a+b+c;
    // ll lsa = a < ou[0].size() ? ou[0][a] : n;
    // ll lsb = b < ou[1].size() ? ou[1][b] : n;
    // ll lsc = c < ou[2].size() ? ou[2][c] : n;
    // auto costFor = [&](ll col, ll t) {
    //     int ans = 0;
    //     ptr[col][0] = 0;
    //     // while (ptr[col][0] >= 0 && ou[0][ptr[col][0]] > ou[col][t]) ptr[col][0]--;
    //     while (ptr[col][0] < ou[0].size() && ou[0][ptr[col][0]] < ou[col][t]) ptr[col][0]++;
    //     ans += min((int)a, ptr[col][0]);
    //     // for (ll j = 0; j < a; j++) if (ou[0][j] < ou[col][t]) ans++;
    //     for (ll j = 0; j < a; j++) if (ou[0][j] < ou[col][t]) ans++;
    //     for (ll j = 0; j < b; j++) if (ou[1][j] < ou[col][t]) ans++;
    //     for (ll j = 0; j < c; j++) if (ou[2][j] < ou[col][t]) ans++;
    //     return ans;
    // };
    if (last != 0 && a < ou[0].size()) { ans = min(ans, solve(a+1, b, c, 0) + ou[0][a] - fcost(a, b, c, 0)); }
    if (last != 1 && b < ou[1].size()) { ans = min(ans, solve(a, b+1, c, 1) + ou[1][b] - fcost(a, b, c, 1)); }
    if (last != 2 && c < ou[2].size()) { ans = min(ans, solve(a, b, c+1, 2) + ou[2][c] - fcost(a, b, c, 2)); }
    return ans;
}

int main () {
    cin.tie(nullptr) -> sync_with_stdio(false);
    cin >> n;
    string str;
    cin >> str;
    // ou[0] = ou[1] = ou[2] = { -1 };
    for (ll i = 0; i < n; i++) {
        ou[(str[i] == 'R' ? 0 : str[i] == 'G' ? 1 : 2)].push_back(i);
    }
    ll ans = min({ solve(0, 0, 0, 0), solve(0, 0, 0, 1), solve(0, 0, 0, 2) });
    cout << (ans == 1e9 ? -1 : ans) << '\n';
    return 0;
}

Compilation message (stderr)

joi2019_ho_t3.cpp:9:27: warning: multi-line comment [-Wcomment]
    9 | int dp[403][403][403][3]; // dp[a][b][c][last] = min operations to have a valid string\
      |                           ^
joi2019_ho_t3.cpp: In function 'int solve(ll, ll, ll, ll)':
joi2019_ho_t3.cpp:55:24: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |     if (last != 0 && a < ou[0].size()) { ans = min(ans, solve(a+1, b, c, 0) + ou[0][a] - fcost(a, b, c, 0)); }
      |                      ~~^~~~~~~~~~~~~~
joi2019_ho_t3.cpp:56:24: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |     if (last != 1 && b < ou[1].size()) { ans = min(ans, solve(a, b+1, c, 1) + ou[1][b] - fcost(a, b, c, 1)); }
      |                      ~~^~~~~~~~~~~~~~
joi2019_ho_t3.cpp:57:24: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |     if (last != 2 && c < ou[2].size()) { ans = min(ans, solve(a, b, c+1, 2) + ou[2][c] - fcost(a, b, c, 2)); }
      |                      ~~^~~~~~~~~~~~~~
joi2019_ho_t3.cpp:39:9: warning: unused variable 'i' [-Wunused-variable]
   39 |     int i = a+b+c;
      |         ^

• Subtask 1: 5 / 5
• Subtask 2: 55 / 55
• Subtask 3: 0 / 15
• Subtask 4: 0 / 25