#include <bits/stdc++.h> using namespace std; long long PRIME = 1000000007; struct BSTNode { long long sumID; long long result; long long sumLeft; long long sumRight; BSTNode* left; BSTNode* right; }; BSTNode* newNode(BSTNode* node, long long sumID){ node = new BSTNode; node->sumID = sumID; node->result = 0; node->sumLeft = 0; node->sumRight = 0; node->left = nullptr; node->right = nullptr; return node; } long long sumLessOrEqual(BSTNode* node, long long valueID) { if(node == nullptr) return 0; if(node->sumID <= valueID) { return node->result + node->sumLeft + sumLessOrEqual(node->right, valueID); } else { return sumLessOrEqual(node->left, valueID); } } long long sumGreater(BSTNode* node, long long valueID) { if(node == nullptr) return 0; if(node->sumID > valueID) { return node->result + node->sumRight + sumGreater(node->left, valueID); } else { return sumGreater(node->right, valueID); } } void updateResult(BSTNode* node, long long sumID, long long newResult) { if(sumID == node->sumID) { node->result += newResult; } else if(sumID < node->sumID) { updateResult(node->left, sumID, newResult); node->sumLeft += newResult; } else { updateResult(node->right, sumID, newResult); node->sumRight += newResult; } } BSTNode* insertFromSortedUniqueVector(vector<long long>& sums, int start, int end){ if(start>end) { return nullptr; } BSTNode *root; int mid = (start + end)/2; root = newNode(root, sums[mid]); // root->left = insertFromSortedUniqueVector(sums, start,mid - 1); root->right = insertFromSortedUniqueVector(sums, mid + 1, end); return root; } long long mopadulo(long long number, long long prime=PRIME){ return ((number+prime) % prime) % 2; } BSTNode* insertFromVector(vector<long long> sums, long long modFilter) { sort(sums.begin(), sums.end()); vector<long long> filtered; long long prev = -1; for(long long & sum : sums) { if(mopadulo(sum) == modFilter and sum != prev){ filtered.push_back(sum); prev = sum; } } return insertFromSortedUniqueVector(filtered, 0, filtered.size()-1); } long long nLoGNSolution(){ long long n, nextNumber; cin >> n; vector<long long> sums; long long sum = 0; sums.push_back(0); for(int i = 0; i < n; i++){ cin >> nextNumber; sum += nextNumber; sums.push_back(sum%PRIME); } BSTNode* root0 = insertFromVector(sums, 0); BSTNode* root1 = insertFromVector(sums, 1); long long result; for(int i = 0; i < n; i++){ long long mod = mopadulo(sums[i+1]); if(mod == 1) { result = sumLessOrEqual(root1, sums[i+1]) + sumGreater(root0, sums[i+1]); updateResult(root1, sums[i+1], result%PRIME); } else { result = sumLessOrEqual(root0, sums[i+1]) + sumGreater(root1, sums[i+1]) + 1; updateResult(root0, sums[i+1], result%PRIME); } } return result%PRIME; } int main() { std::ios_base::sync_with_stdio(false); cout<<nLoGNSolution()<<endl; return 0; }
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 | #include <bits/stdc++.h> using namespace std; long long PRIME = 1000000007; struct BSTNode { long long sumID; long long result; long long sumLeft; long long sumRight; BSTNode* left; BSTNode* right; }; BSTNode* newNode(BSTNode* node, long long sumID){ node = new BSTNode; node->sumID = sumID; node->result = 0; node->sumLeft = 0; node->sumRight = 0; node->left = nullptr; node->right = nullptr; return node; } long long sumLessOrEqual(BSTNode* node, long long valueID) { if(node == nullptr) return 0; if(node->sumID <= valueID) { return node->result + node->sumLeft + sumLessOrEqual(node->right, valueID); } else { return sumLessOrEqual(node->left, valueID); } } long long sumGreater(BSTNode* node, long long valueID) { if(node == nullptr) return 0; if(node->sumID > valueID) { return node->result + node->sumRight + sumGreater(node->left, valueID); } else { return sumGreater(node->right, valueID); } } void updateResult(BSTNode* node, long long sumID, long long newResult) { if(sumID == node->sumID) { node->result += newResult; } else if(sumID < node->sumID) { updateResult(node->left, sumID, newResult); node->sumLeft += newResult; } else { updateResult(node->right, sumID, newResult); node->sumRight += newResult; } } BSTNode* insertFromSortedUniqueVector(vector<long long>& sums, int start, int end){ if(start>end) { return nullptr; } BSTNode *root; int mid = (start + end)/2; root = newNode(root, sums[mid]); // root->left = insertFromSortedUniqueVector(sums, start,mid - 1); root->right = insertFromSortedUniqueVector(sums, mid + 1, end); return root; } long long mopadulo(long long number, long long prime=PRIME){ return ((number+prime) % prime) % 2; } BSTNode* insertFromVector(vector<long long> sums, long long modFilter) { sort(sums.begin(), sums.end()); vector<long long> filtered; long long prev = -1; for(long long & sum : sums) { if(mopadulo(sum) == modFilter and sum != prev){ filtered.push_back(sum); prev = sum; } } return insertFromSortedUniqueVector(filtered, 0, filtered.size()-1); } long long nLoGNSolution(){ long long n, nextNumber; cin >> n; vector<long long> sums; long long sum = 0; sums.push_back(0); for(int i = 0; i < n; i++){ cin >> nextNumber; sum += nextNumber; sums.push_back(sum%PRIME); } BSTNode* root0 = insertFromVector(sums, 0); BSTNode* root1 = insertFromVector(sums, 1); long long result; for(int i = 0; i < n; i++){ long long mod = mopadulo(sums[i+1]); if(mod == 1) { result = sumLessOrEqual(root1, sums[i+1]) + sumGreater(root0, sums[i+1]); updateResult(root1, sums[i+1], result%PRIME); } else { result = sumLessOrEqual(root0, sums[i+1]) + sumGreater(root1, sums[i+1]) + 1; updateResult(root0, sums[i+1], result%PRIME); } } return result%PRIME; } int main() { std::ios_base::sync_with_stdio(false); cout<<nLoGNSolution()<<endl; return 0; } |