#include<bits/stdc++.h> #define ll long long #define pii pair<int, int> #define st first #define nd second #define turbo ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0); #define pb push_back #define vi vector<int> #define vvi vector<vi> #define qi queue<int> #define ld long double using namespace std; /*---------------------------------------------------------///CODE///---------------------------------------------------------*/ const ll MAX = 1LL << 30; const ll MOD = 1e9 + 7; struct Node { pair<ll, ll> value; Node *l, *r; Node(): l(NULL), r(NULL) { value = {0, 0}; } }; ll getvalue(Node* v, bool x) { if(v == NULL) return 0; if(!x) return (v -> value).st; else return (v -> value).nd; } Node* getl(Node* v) { if(v -> l == NULL) return v -> l = new Node(); return v -> l; } Node* getr(Node* v) { if(v -> r == NULL) return v -> r = new Node(); return v -> r; } ll Query(ll a, ll b, bool x, ll lo, ll hi, Node* v) { if(a > b) return 0; if(lo >= a && hi <= b) return getvalue(v, x); if(lo > b || hi < a) return 0; ll mid = (lo + hi) >> 1; return (Query(a, b, x, lo, mid, getl(v)) + Query(a, b, x, mid + 1, hi, getr(v))) % MOD; } void Update(ll p, bool x, ll lo, ll hi, Node* v, ll ile) { if(lo == hi && lo == p) { if(!x) (v -> value).st = ((v -> value).st + ile) % MOD; else (v -> value).nd = ((v -> value).nd + ile) % MOD; return; } if(lo > p || hi < p) return; ll mid = (lo + hi) >> 1; Update(p, x, lo, mid, getl(v), ile); Update(p, x, mid + 1, hi, getr(v), ile); v -> value = {(getvalue(v -> l, 0) + getvalue(v -> r, 0)) % MOD, (getvalue(v -> l, 1) + getvalue(v -> r, 1)) % MOD}; } int main() { turbo Node* Tree = new Node(); int n; cin >> n; ll start = 0; vector<ll> v(n); for(int i = 0; i < n; i++) cin >> v[i]; Update(v[0], v[0] % 2, 0, MAX - 1, Tree, 1); for(int i = 1; i < n; i++) { ll sum = (Query(start, MOD - 1, start % 2, 0, MAX - 1, Tree) + Query(0, start - 1, (start % 2) ^ 1, 0, MAX - 1, Tree)) % MOD; start = (start - v[i] + MOD) % MOD; Update((start + v[i]) % MOD, ((start + v[i]) % MOD) % 2, 0, MAX - 1, Tree, sum); } cout << (Query(start, MOD - 1, start % 2, 0, MAX - 1, Tree) + Query(0, start - 1, (start % 2) ^ 1, 0, MAX - 1, Tree)) % MOD; 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 | #include<bits/stdc++.h> #define ll long long #define pii pair<int, int> #define st first #define nd second #define turbo ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0); #define pb push_back #define vi vector<int> #define vvi vector<vi> #define qi queue<int> #define ld long double using namespace std; /*---------------------------------------------------------///CODE///---------------------------------------------------------*/ const ll MAX = 1LL << 30; const ll MOD = 1e9 + 7; struct Node { pair<ll, ll> value; Node *l, *r; Node(): l(NULL), r(NULL) { value = {0, 0}; } }; ll getvalue(Node* v, bool x) { if(v == NULL) return 0; if(!x) return (v -> value).st; else return (v -> value).nd; } Node* getl(Node* v) { if(v -> l == NULL) return v -> l = new Node(); return v -> l; } Node* getr(Node* v) { if(v -> r == NULL) return v -> r = new Node(); return v -> r; } ll Query(ll a, ll b, bool x, ll lo, ll hi, Node* v) { if(a > b) return 0; if(lo >= a && hi <= b) return getvalue(v, x); if(lo > b || hi < a) return 0; ll mid = (lo + hi) >> 1; return (Query(a, b, x, lo, mid, getl(v)) + Query(a, b, x, mid + 1, hi, getr(v))) % MOD; } void Update(ll p, bool x, ll lo, ll hi, Node* v, ll ile) { if(lo == hi && lo == p) { if(!x) (v -> value).st = ((v -> value).st + ile) % MOD; else (v -> value).nd = ((v -> value).nd + ile) % MOD; return; } if(lo > p || hi < p) return; ll mid = (lo + hi) >> 1; Update(p, x, lo, mid, getl(v), ile); Update(p, x, mid + 1, hi, getr(v), ile); v -> value = {(getvalue(v -> l, 0) + getvalue(v -> r, 0)) % MOD, (getvalue(v -> l, 1) + getvalue(v -> r, 1)) % MOD}; } int main() { turbo Node* Tree = new Node(); int n; cin >> n; ll start = 0; vector<ll> v(n); for(int i = 0; i < n; i++) cin >> v[i]; Update(v[0], v[0] % 2, 0, MAX - 1, Tree, 1); for(int i = 1; i < n; i++) { ll sum = (Query(start, MOD - 1, start % 2, 0, MAX - 1, Tree) + Query(0, start - 1, (start % 2) ^ 1, 0, MAX - 1, Tree)) % MOD; start = (start - v[i] + MOD) % MOD; Update((start + v[i]) % MOD, ((start + v[i]) % MOD) % 2, 0, MAX - 1, Tree, sum); } cout << (Query(start, MOD - 1, start % 2, 0, MAX - 1, Tree) + Query(0, start - 1, (start % 2) ^ 1, 0, MAX - 1, Tree)) % MOD; return 0; } |