#include <algorithm> #include <array> #include <iostream> #include <vector> using ll = long long; constexpr char OFFICE = '1'; constexpr char REMOTE = '2'; constexpr char NOMEET = '3'; constexpr int MAXN = 8000; constexpr int INFTY = 2 * MAXN; int main() { std::ios_base::sync_with_stdio(0); std::cin.tie(0); int n, k, t; std::cin >> n >> k >> t; std::string word; std::cin >> word; word.insert(word.begin(), '.'); word.push_back(NOMEET); std::vector<int> prefsum_meetings(n+1); for (int i = 1; i <= n; ++i) { prefsum_meetings[i] = prefsum_meetings[i-1] + (word[i] != NOMEET); } k = std::min(k, prefsum_meetings[n]); // dp[0/1][i][s] -- max number of fun hours in length=i prefix if skipped =s meetings and i-th hour spent at home/work. std::array<std::vector<std::vector<int>>, 2> dp {{ std::vector<std::vector<int>>(n+2, std::vector<int>(k + 1)), std::vector<std::vector<int>>(n+2, std::vector<int>(k + 1)), }}; // Count the number of meetings of either kind on [p, q] auto count_meetings = [&](int p, int q) -> int { return prefsum_meetings[q] - prefsum_meetings[p - 1]; }; for (int i = 1; i <= n+1; ++i) { for (int s = 0; s <= k; ++s) { int departed = i - t; bool can_drive = departed >= 1; int drive_skipped; if (can_drive) { drive_skipped = count_meetings(i - t, i - 1); can_drive = s >= drive_skipped; } int sofar_if_noskip[2]; int sofar_if_skip[2]; for (int loc : {0, 1}) { sofar_if_noskip[loc] = std::max(can_drive ? dp[loc^1][departed - 1][s - drive_skipped] : -INFTY, dp[loc][i - 1][s]); sofar_if_skip[loc] = s > 0 ? std::max(can_drive && s - drive_skipped >= 1 ? dp[loc^1][departed - 1][s - drive_skipped - 1] : -INFTY, dp[loc][i - 1][s - 1]) : -INFTY; } if (word[i] == NOMEET) { dp[0][i][s] = sofar_if_noskip[0] + 1; dp[1][i][s] = departed >= 1 ? sofar_if_noskip[1] : -INFTY; } else if (word[i] == REMOTE) { dp[0][i][s] = std::max(sofar_if_noskip[0], sofar_if_skip[0] + 1); dp[1][i][s] = departed >= 1 ? std::max(sofar_if_noskip[1], sofar_if_skip[1]) : -INFTY; } else if (word[i] == OFFICE) { dp[0][i][s] = s > 0 ? sofar_if_skip[0] + 1 : -INFTY; dp[1][i][s] = departed >= 1 ? std::max(sofar_if_noskip[1], sofar_if_skip[1]) : -INFTY; } else { __builtin_unreachable(); } } } // for (int i = 1; i <= n+1; ++i) { // std::cout << "dp[0][i="<<i<<"]:"; // for (int s = 0; s <= k; ++s) { // std::cout << ' ' << dp[0][i][s]; // } // std::cout << '\n'; // std::cout << "dp[1][i="<<i<<"]:"; // for (int s = 0; s <= k; ++s) { // std::cout << ' ' << dp[1][i][s]; // } // std::cout << '\n'; // } int answer = -INFTY; for (int s = 0; s <= k; ++s) { answer = std::max(answer, dp[0][n+1][s] - 1); } if (answer < 0) { answer = -1; } std::cout << answer << '\n'; /* std::vector<int> prefsum_remote(n+1); std::vector<int> prefsum_office(n+1); for (int i = 1; i <= n; ++i) { prefsum_remote[i] = prefsum_remote[i-1] + (word[i -1] == REMOTE); prefsum_office[i] = prefsum_office[i-1] + (word[i -1] == OFFICE); } // L[i] -- # of meetings skipped by leaving for work at i // R[i] -- # of meetings skipped by leaving work at i std::vector<int> L(n+1); std::vector<int> R(n+1); for (int i = 1; i + t - 1 <= n; ++i) { L[i] = ( prefsum_office[i + t - 1] + prefsum_remote[i + t - 1] - prefsum_remote[i - 1] ); R[i] = ( prefsum_office[n] - prefsum_office[i - 1] + prefsum_remote[i + t - 1] - prefsum_remote[i - 1] ); } std::vector<int> prefmin_L(n+1); std::vector<int> sm_R(n+1); */ }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | #include <algorithm> #include <array> #include <iostream> #include <vector> using ll = long long; constexpr char OFFICE = '1'; constexpr char REMOTE = '2'; constexpr char NOMEET = '3'; constexpr int MAXN = 8000; constexpr int INFTY = 2 * MAXN; int main() { std::ios_base::sync_with_stdio(0); std::cin.tie(0); int n, k, t; std::cin >> n >> k >> t; std::string word; std::cin >> word; word.insert(word.begin(), '.'); word.push_back(NOMEET); std::vector<int> prefsum_meetings(n+1); for (int i = 1; i <= n; ++i) { prefsum_meetings[i] = prefsum_meetings[i-1] + (word[i] != NOMEET); } k = std::min(k, prefsum_meetings[n]); // dp[0/1][i][s] -- max number of fun hours in length=i prefix if skipped =s meetings and i-th hour spent at home/work. std::array<std::vector<std::vector<int>>, 2> dp {{ std::vector<std::vector<int>>(n+2, std::vector<int>(k + 1)), std::vector<std::vector<int>>(n+2, std::vector<int>(k + 1)), }}; // Count the number of meetings of either kind on [p, q] auto count_meetings = [&](int p, int q) -> int { return prefsum_meetings[q] - prefsum_meetings[p - 1]; }; for (int i = 1; i <= n+1; ++i) { for (int s = 0; s <= k; ++s) { int departed = i - t; bool can_drive = departed >= 1; int drive_skipped; if (can_drive) { drive_skipped = count_meetings(i - t, i - 1); can_drive = s >= drive_skipped; } int sofar_if_noskip[2]; int sofar_if_skip[2]; for (int loc : {0, 1}) { sofar_if_noskip[loc] = std::max(can_drive ? dp[loc^1][departed - 1][s - drive_skipped] : -INFTY, dp[loc][i - 1][s]); sofar_if_skip[loc] = s > 0 ? std::max(can_drive && s - drive_skipped >= 1 ? dp[loc^1][departed - 1][s - drive_skipped - 1] : -INFTY, dp[loc][i - 1][s - 1]) : -INFTY; } if (word[i] == NOMEET) { dp[0][i][s] = sofar_if_noskip[0] + 1; dp[1][i][s] = departed >= 1 ? sofar_if_noskip[1] : -INFTY; } else if (word[i] == REMOTE) { dp[0][i][s] = std::max(sofar_if_noskip[0], sofar_if_skip[0] + 1); dp[1][i][s] = departed >= 1 ? std::max(sofar_if_noskip[1], sofar_if_skip[1]) : -INFTY; } else if (word[i] == OFFICE) { dp[0][i][s] = s > 0 ? sofar_if_skip[0] + 1 : -INFTY; dp[1][i][s] = departed >= 1 ? std::max(sofar_if_noskip[1], sofar_if_skip[1]) : -INFTY; } else { __builtin_unreachable(); } } } // for (int i = 1; i <= n+1; ++i) { // std::cout << "dp[0][i="<<i<<"]:"; // for (int s = 0; s <= k; ++s) { // std::cout << ' ' << dp[0][i][s]; // } // std::cout << '\n'; // std::cout << "dp[1][i="<<i<<"]:"; // for (int s = 0; s <= k; ++s) { // std::cout << ' ' << dp[1][i][s]; // } // std::cout << '\n'; // } int answer = -INFTY; for (int s = 0; s <= k; ++s) { answer = std::max(answer, dp[0][n+1][s] - 1); } if (answer < 0) { answer = -1; } std::cout << answer << '\n'; /* std::vector<int> prefsum_remote(n+1); std::vector<int> prefsum_office(n+1); for (int i = 1; i <= n; ++i) { prefsum_remote[i] = prefsum_remote[i-1] + (word[i -1] == REMOTE); prefsum_office[i] = prefsum_office[i-1] + (word[i -1] == OFFICE); } // L[i] -- # of meetings skipped by leaving for work at i // R[i] -- # of meetings skipped by leaving work at i std::vector<int> L(n+1); std::vector<int> R(n+1); for (int i = 1; i + t - 1 <= n; ++i) { L[i] = ( prefsum_office[i + t - 1] + prefsum_remote[i + t - 1] - prefsum_remote[i - 1] ); R[i] = ( prefsum_office[n] - prefsum_office[i - 1] + prefsum_remote[i + t - 1] - prefsum_remote[i - 1] ); } std::vector<int> prefmin_L(n+1); std::vector<int> sm_R(n+1); */ } |