Submission #1281646

#	Time	Username	Problem	Language	Result	Execution time	Memory
1281646		cjspd_oly	Miners (IOI07_miners)	C++17	100 / 100	32 ms	648 KiB

miners

#include <bits/stdc++.h>

using namespace std;

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;

using pii = pair<int, int>;
using vii = vector<pii>;
using vvii = vector<vii>;

using l = long long;
using vl = vector<l>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;

using pll = pair<l, l>;
using vll = vector<pll>;
using vvll = vector<vll>;

using d = double;
using vd = vector<d>;
using vvd = vector<vd>;
using vvvd = vector<vvd>;

using ld = long double;
using vld = vector<ld>;
using vvld = vector<vld>;
using vvvld = vector<vvld>;

using vb = vector<bool>;
using vvb = vector<vb>;
using pbb = pair<bool, bool>;
using vbb = vector<pbb>;

#define ff first
#define ss second

#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()

void setIO(string name = "")
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (!name.empty())
    {
        (void)freopen((name + ".in").c_str(), "r", stdin);
        (void)freopen((name + ".out").c_str(), "w", stdout);
    }
}

const ld pi = 3.14159265358979323846;

const l LINF = 1e18;
const l INF = 1e9;

const l MOD = 1e9 + 7;
// const l MOD = 998244353;

const l MAXN = 2e5 + 5;

int gain(int a, int b, int c)
{
    bool used[4] = {0};
    if (a)
        used[a] = true;
    if (b)
        used[b] = true;
    if (c)
        used[c] = true;
    return used[1] + used[2] + used[3];
}

int mp(char ch)
{
    if (ch == 'M')
        return 1;
    if (ch == 'F')
        return 2;
    if (ch == 'B')
        return 3;
    return 0; // * none
}

int dp[2][4][4][4][4]; // * DP [prev/cur][mine1 last two foods][mine2 last two foods]

void solve()
{
    
    int n;
    string s;
    cin >> n >> s;

    memset(dp, -1, sizeof(dp));
    dp[0][0][0][0][0] = 0;

    for (int i = 0; i < n; ++i) {
        int x = mp(s[i]);
        int cur = i & 1, nxt = cur ^ 1; // * alternate indices similar to swap dp[prev] & dp[next]
        memset(dp[nxt], -1, sizeof(dp[nxt]));

        for (int a = 0; a < 4; ++a)
        for (int b = 0; b < 4; ++b)
        for (int c = 0; c < 4; ++c)
        for (int d = 0; d < 4; ++d) {
            if (dp[cur][a][b][c][d] == -1) continue;
            int base = dp[cur][a][b][c][d];

            int coal1 = gain(x, a, b);
            dp[nxt][x][a][c][d] = max(dp[nxt][x][a][c][d], base + coal1);

            int coal2 = gain(x, c, d);
            dp[nxt][a][b][x][c] = max(dp[nxt][a][b][x][c], base + coal2);
        }
    }

    int ans = 0;
    int last = n & 1;
    for (int a = 0; a < 4; ++a)
    for (int b = 0; b < 4; ++b)
    for (int c = 0; c < 4; ++c)
    for (int d = 0; d < 4; ++d)
        ans = max(ans, dp[last][a][b][c][d]);

    cout << ans << '\n';
}

int main()
{
    setIO("");

#ifndef ONLINE_JUDGE
    // setIO("filename");
#endif

    int t = 1;
    // cin >> t;
    while (t--)
        solve();

    return 0;
}

Compilation message (stderr)

miners.cpp: In function 'void setIO(std::string)':
miners.cpp:52:22: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |         (void)freopen((name + ".in").c_str(), "r", stdin);
      |               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
miners.cpp:53:22: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |         (void)freopen((name + ".out").c_str(), "w", stdout);
      |               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 7 / 7
• Subtask 7: 8 / 8
• Subtask 8: 8 / 8
• Subtask 9: 8 / 8
• Subtask 10: 8 / 8
• Subtask 11: 8 / 8
• Subtask 12: 8 / 8