D:
/*CodeForces 920D - Tanks [ DP ]核心思想是判断是否能用 a[i]%k 来构成 V%kDP并记录路径即可,剩下的就是加K减K操作*/#includeusing namespace std;#define LL long longconst int N = 5005;int n, k ,v;LL a[N];int b[N], d[N][N], pre[N][N];bool used[N];struct Ans { int cnt, x, y;};vector ans;bool solve() { for (int i = 1; i <= n; i++) if (v == a[i]) return 1; if (v == 0) { ans.push_back(Ans{(a[1]-1)/k+1,1,2}); return 1; } d[0][0] = 1; for (int i = 1; i <= n; i++) { for (int j = 0; j <= k; j++) { if (d[i-1][j]) d[i][j] = 1, pre[i][j] = j; else if (d[i-1][(j-b[i]+k)%k]) d[i][j] = 1, pre[i][j] = (j-b[i]+k)%k; } } if (!d[n][v%k]) return 0; for (int i = n, j = v%k; i >= 1; j = pre[i][j], i--) { if (pre[i][j] != j) used[i] = 1; } int chose = 0; for (int i = 1; i <= n; i++) { if (used[i]) chose = i; } for (int i = 1; i <= n; i++){ if (chose && i != chose && used[i]) { ans.push_back(Ans{(a[i]-1)/k+1, i, chose}); used[i] = 0; a[chose] += a[i]; a[i] = 0; } } int nchose = 0; for (int i = 1; i <= n; i++) { if (!used[i]) nchose = i; } for (int i = 1; i <= n; i++) { if (nchose && i != nchose && a[i] && !used[i]) { ans.push_back(Ans{(a[i]-1)/k+1, i, nchose}); a[nchose] += a[i]; a[i] = 0; } } if (!chose) chose = 1; if (a[chose] + a[nchose] < v) return 0; if (a[chose] > v) ans.push_back(Ans{(a[chose]-v)/k, chose, nchose}); else if (a[chose] < v) ans.push_back(Ans{(v-a[chose])/k, nchose, chose}); return 1;}int main() { scanf("%d%d%d", &n, &k, &v); for (int i = 1; i <= n; i++) scanf("%lld", &a[i]), b[i] = a[i]%k; if (!solve()) puts("NO"); else { puts("YES"); for (auto a : ans) printf("%d %d %d\n", a.cnt, a.x, a.y); }}
E:
/*CodeForces 920E - Connected Components? [ 并查集 ]用并查集跳过不用继续查询的连续区间*/#includeusing namespace std;typedef pair P;const int N = 200005;int n, m;vector ans;map mp;int f[N];int sf(int x) { return x == f[x] ? x : f[x] = sf(f[x]);}int fa[N];queue Q;int BFS(int st) { int res = 0; while (!Q.empty()) Q.pop(); Q.push(st); fa[st] = st; f[st] = sf(st+1); res++; while (!Q.empty()) { int u = Q.front(); Q.pop(); for (int v = sf(1); v <= n; v = sf(v+1)) { if (mp[P(u,v)] || v == u) continue; fa[v] = st; f[v] = sf(v+1); res++; Q.push(v); } } return res;}int main() { scanf("%d%d", &n, &m); for (int i = 1; i <= m; i++) { int u, v; scanf("%d%d", &u, &v); mp[P(u, v)] = mp[P(v, u)] = 1; } for (int i = 1; i <= n+1; i++) f[i] = i; for (int i = 1; i <= n; i++) if (!fa[i]) ans.push_back(BFS(i)); sort(ans.begin(), ans.end()); printf("%d\n", ans.size()); for (int i = 0; i < ans.size()-1; i++) printf("%d ", ans[i]); printf("%d\n", ans[ans.size()-1]);}
F:
/*CodeForces 920F - SUM and REPLACE [ 线段树 ]D(n)下降快,不动点有两个,下降至不动点时不更新即可*/#includeusing namespace std;#define LL long longconst int N = 3e5+5;const int M = 1e6+5;int n, m;int a[N];int D[M];void init() { for (int i = 1; i < M; i++) for (int j = i; j < M; j += i) D[j]++;}LL sum[N<<2], Max[N<<2];void up(int x) { sum[x] = sum[x<<1] + sum[x<<1|1]; Max[x] = max(Max[x<<1], Max[x<<1|1]);}void build(int l, int r, int x) { if (l == r) { sum[x] = Max[x] = a[l]; return; } int mid = (l+r) >> 1; build(l, mid, x<<1); build(mid+1, r, x<<1|1); up(x);}void change(int L, int R, int l, int r, int x) { if (L <= l && r <= R && Max[x] == 1 || Max[x] == 2) return; if (l == r) { sum[x] = Max[x] = D[sum[x]]; return; } int mid = (l+r)>>1; if (L <= mid) change(L, R, l, mid, x<<1); if (mid < R) change(L, R, mid+1, r, x<<1|1); up(x);}LL query(int L, int R, int l, int r, int x) { if (L <= l && r <= R) return sum[x]; int mid = (l+r) >> 1; LL res = 0; if (L <= mid) res += query(L, R, l, mid, x<<1); if (R > mid) res += query(L, R, mid+1, r, x<<1|1); return res;}int main() { init(); scanf("%d%d", &n, &m); for (int i = 1; i <= n; i++) scanf("%d", &a[i]); build(1, n, 1); while (m--) { int t, l, r; scanf("%d%d%d", &t, &l, &r); if (t == 1) change(l, r, 1, n, 1); else printf("%lld\n", query(l, r, 1, n, 1)); }}
G:
/*CodeForces 920G - List Of Integers [ 容斥,二分 ]二分找答案,计算用容斥*/#includeusing namespace std;const int N = 1e6+5;bool notp[N];int prime[N], pnum, mu[N];void Mobius() { memset(notp, 0, sizeof(notp)); mu[1] = 1; for (int i = 2; i < N; i++) { if (!notp[i]) prime[++pnum] = i, mu[i] = -1; for (int j = 1; prime[j]*i < N; j++) { notp[prime[j]*i] = 1; if (i%prime[j] == 0) { mu[prime[j]*i] = 0; break; } mu[prime[j]*i] = -mu[i]; } }}int t, x, p, k;int Cal(int l, int r) { int res = 0; for (int i = 1; i*i <= p; i++) { if (p%i == 0) { res += mu[i] * (r/i-(l-1)/i); if (p/i != i) res += mu[p/i] * (r/(p/i) - (l-1)/(p/i)); } } return res;}int BinaryFind(int l, int r, int k) { while (l <= r) { int mid = (l+r) >> 1; if (Cal(x+1, mid) < k) l = mid+1; else r = mid-1; } return l;}int main() { Mobius(); scanf("%d", &t); while (t--) { scanf("%d%d%d", &x, &p, &k); printf("%d\n", BinaryFind(x+1, 1e8, k)); }}