P1182 數列分段 Section II
阿新 • • 發佈:2022-03-15
// Problem: P1182 數列分段 Section II // Contest: Luogu // URL: https://www.luogu.com.cn/problem/P1182 // Memory Limit: 125 MB // Time Limit: 1000 ms // User: Pannnn #include <bits/stdc++.h> using namespace std; template<class T> void debugVector(const T &a) { cout << "[ "; for (size_t i = 0; i < a.size(); ++i) { cout << a[i] << (i == a.size() - 1 ? " " : ", "); } cout << "]" << endl; } template<class T1, class T2> void debugVectorPair(const vector<pair<T1, T2>> &a) { cout << "{"; for (size_t i = 0; i < a.size(); ++i) { cout << "[ " << a[i].first << ": " << a[i].second << (i == a.size() - 1 ? " ]" : " ], "); } cout << "}" << endl; } template<class T> void debugMatrix2(const T &a) { for (size_t i = 0; i < a.size(); ++i) { debugVector(a[i]); } } template<class T> using matrix2 = vector<vector<T>>; template<class T> vector<vector<T>> getMatrix2(size_t n, size_t m, T init = T()) { return vector<vector<T>>(n, vector<T>(m, init)); } template<class T> using matrix3 = vector<vector<vector<T>>>; template<class T> vector<vector<vector<T>>> getMatrix3(size_t x, size_t y, size_t z, T init = T()) { return vector<vector<vector<T>>>(x, vector<vector<T>>(y, vector<T>(z, init))); } vector<int> genBigInteger(const string &a) { vector<int> res; if (a.empty()) return res; for (int i = a.size() - 1; i >= 0; --i) { res.push_back(a[i] - '0'); } return res; } ostream &printBigInteger(const vector<int> &a) { if (a.empty()) return cout; for (int i = a.size() - 1; i >= 0; --i) { cout << a[i]; } return cout; } vector<int> maxBigInteger(const vector<int> &a, const vector<int> &b) { if (a.size() > b.size()) { return a; } else if (a.size() < b.size()) { return b; } for (int i = a.size() - 1; i >= 0; --i) { if (a[i] > b[i]) { return a; } else if (a[i] < b[i]) { return b; } } return a; } vector<int> addBigInteger(const vector<int> &a, const vector<int> &b) { vector<int> res; int pre = 0; for (size_t i = 0; i < a.size() || i < b.size() || pre; ++i) { if (i < a.size()) pre += a[i]; if (i < b.size()) pre += b[i]; res.push_back(pre % 10); pre /= 10; } while (res.size() > 1 && res.back() == 0) { res.pop_back(); } return res; } vector<int> mulBigInteger(const vector<int> &a, int b) { vector<int> res; int pre = 0; for (size_t i = 0; i < a.size() || pre; ++i) { if (i < a.size()) pre += a[i] * b; res.push_back(pre % 10); pre /= 10; } while (res.size() > 1 && res.back() == 0) { res.pop_back(); } return res; } vector<int> divBigInteger(const vector<int> &a, int b, int &r) { vector<int> res; for (int i = a.size() - 1; i >= 0; --i) { r = 10 * r + a[i]; res.push_back(r / b); r %= b; } reverse(res.begin(), res.end()); while (res.size() > 1 && res.back() == 0) { res.pop_back(); } return res; } bool check(vector<long long> &info, long long mid, int m) { int cnt = 1; long long tSum = 0; for (int i = 0; i < info.size(); ++i) { if (tSum + info[i] > mid) { tSum = info[i]; ++cnt; } else { tSum += info[i]; } } return cnt <= m; } /* 二分的左邊界為陣列中最大值,右邊界為陣列元素和。 之所以左邊界不從0開始,是由於若陣列中有一個較大值,而此時目標mid較小,則也會認為此mid值合法僅增加一次計數。 */ int main() { ios::sync_with_stdio(false); cin.tie(0); int n, m; cin >> n >> m; vector<long long> info(n); long long left = 0, right = 0; for (int i = 0; i < n; ++i) { cin >> info[i]; left = max(left, info[i]); right += info[i]; } while (left < right) { long long mid = (left + right) >> 1; if (check(info, mid, m)) { right = mid; } else { left = mid + 1; } } cout << right << endl; return 0; }