noip刷题记录 20170818
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天天爱跑步
lca + 树上差分
#include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<string> #include<cmath> #include<algorithm> #include<vector> using namespace std; const int N = 3e5 + 5, M = 3e5 + 5; int n, m, ans[N], offset; int ecnt, adj[N], go[M << 1], nxt[M << 1]; int w[N], dep[N], cnt[N << 2], fa[N][25]; struct node{ int val, delta; node(){} node(int a, int b):val(a), delta(b){} }; vector<node> tag[N]; inline void addEdge(int u, int v){ nxt[++ecnt] = adj[u], adj[u] = ecnt, go[ecnt] = v; nxt[++ecnt] = adj[v], adj[v] = ecnt, go[ecnt] = u; } inline int getLca(int u, int v){ if(dep[u] < dep[v]) swap(u, v); int delta = dep[u] - dep[v]; for(int i = 20; i >= 0; i--) if((1 << i) & delta) u = fa[u][i]; if(u == v) return u; for(int i = 20; i >= 0; i--) if(fa[u][i] != fa[v][i]) u = fa[u][i], v = fa[v][i]; return fa[u][0]; } inline void dfs(int u, int f){ fa[u][0] = f; for(int i = 1; i <= 20; i++) fa[u][i] = fa[fa[u][i - 1]][i - 1]; for(int e = adj[u], v; e; e = nxt[e]){ v = go[e]; if(v != f){ dep[v] = dep[u] + 1; dfs(v, u); } } } inline void solve(int u){ int cur = cnt[dep[u] + w[u]] + cnt[w[u] - dep[u] + offset]; for(int i = 0; i < tag[u].size(); i++) cnt[tag[u][i].val] += tag[u][i].delta; for(int e = adj[u], v; e; e = nxt[e]){ if((v = go[e]) == fa[u][0]) continue; solve(v); } ans[u] = cnt[dep[u] + w[u]] + cnt[w[u] - dep[u] + offset] - cur; } inline int read(){ int i = 0, f = 1; char ch = getchar(); for(; (ch < ‘0‘ || ch > ‘9‘) && ch != ‘-‘; ch = getchar()); if(ch == ‘-‘) f = -1, ch = getchar(); for(; ch >= ‘0‘ && ch <= ‘9‘; ch = getchar()) i = (i << 3) + (i << 1) + (ch - ‘0‘); return i * f; } inline void wr(int x){ if(x < 0) putchar(‘-‘), x = -x; if(x > 9) wr(x / 10); putchar(x % 10 + ‘0‘); } int main(){ n = read(), m = read(), offset = 3 * n + 1; for(int i = 1; i < n; i++){ int x = read(), y = read(); addEdge(x, y); } dfs(1, 0); for(int i = 1; i <= n; i++) w[i] = read(); for(int i = 1; i <= m; i++){ int s = read(), t = read(), lca = getLca(s, t); tag[s].push_back(node(dep[s], 1)); tag[t].push_back(node(dep[s] - 2 * dep[lca] + offset, 1)); tag[fa[lca][0]].push_back(node(dep[s], -1)); tag[lca].push_back(node(dep[s] - 2 * dep[lca] + offset, -1)); } solve(1); for(int i = 1; i <= n; i++) wr(ans[i]), putchar(‘ ‘); return 0; }
借教室
二分法
#include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<string> #include<algorithm> #include<vector> using namespace std; const int N = 1e6 + 5; int n, m, a[N], f[N], s[N], t[N], d[N], ans; inline int read(){ int i = 0, f = 1; char ch = getchar(); for(; (ch < ‘0‘ || ch > ‘9‘) && ch != ‘-‘; ch = getchar()); if(ch == ‘-‘) f = -1, ch = getchar(); for(; ch >= ‘0‘ && ch <= ‘9‘; ch = getchar()) i = (i << 3) + (i << 1) + (ch - ‘0‘); return i * f; } inline void wr(int x){ if(x < 0) putchar(‘-‘), x = -x; if(x > 9) wr(x / 10); putchar(x % 10 + ‘0‘); } inline bool check(int mid){ int sum = 0; memset(f, 0, sizeof f); for(int i = 1; i <= mid; i++) f[s[i]] += d[i], f[t[i] + 1] -= d[i]; for(int i = 1; i <= n; i++){ sum += f[i]; if(sum > a[i]) return false; } return true; } int main(){ n = read(), m = read(); for(int i = 1; i <= n; i++) a[i] = read(); for(int i = 1; i <= m; i++) d[i] = read(), s[i] = read(), t[i] = read(); int l = 1, r = m; while(l <= r){ int mid = l + r >> 1; if(check(mid)) l = mid + 1; else ans = mid, r = mid - 1; } if(ans == 0) putchar(‘0‘); else{ wr(-1), putchar(‘\n‘); wr(ans); } return 0; }
线段树
#include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<string> #include<cmath> #include<algorithm> using namespace std; const int N = 1e6 + 5, oo = 0x3f3f3f3f; int n, m, minn[N * 4], a[N], tag[N * 4]; inline int read(){ int i = 0, f = 1; char ch = getchar(); for(; (ch < ‘0‘ || ch > ‘9‘) && ch != ‘-‘; ch = getchar()); if(ch == ‘-‘) f = -1, ch = getchar(); for(; ch >= ‘0‘ && ch <= ‘9‘; ch = getchar()) i = (i << 3) + (i << 1) + (ch - ‘0‘); return i * f; } inline void wr(int x){ if(x < 0) putchar(‘-‘), x = -x; if(x > 9) wr(x / 10); putchar(x % 10 + ‘0‘); } inline void build(int k, int l, int r){ if(l == r){ minn[k] = a[l]; return; } int mid = l + r >> 1, lc = k << 1, rc = k << 1 | 1; build(lc, l, mid); build(rc, mid + 1, r); minn[k] = min(minn[lc], minn[rc]); } inline void minuss(int k, int v){ minn[k] -= v; tag[k] += v; } inline void pushDown(int k){ if(tag[k]){ if(minn[k << 1] != -1) minuss(k << 1, tag[k]); if(minn[k << 1 | 1] != -1) minuss(k << 1 | 1, tag[k]); tag[k] = 0; } } inline void modify(int k, int l, int r, int x, int y, int v){ if(x <= l && r <= y){ minuss(k, v); return; } pushDown(k); int mid = l + r >> 1, lc = k << 1, rc = k << 1 | 1, ret = oo; if(x <= mid) modify(lc, l, mid, x, y, v); if(y > mid) modify(rc, mid + 1, r, x, y, v); minn[k] = min(minn[lc], minn[rc]); } inline int query(int k, int l, int r, int x, int y){ if(x <= l && r <= y) return minn[k]; pushDown(k); int mid = l + r >> 1, lc = k << 1, rc = k << 1 | 1, ret = oo; if(x <= mid) ret = min(ret, query(lc, l, mid, x, y)); if(y > mid) ret = min(ret, query(rc, mid + 1, r, x, y)); return ret; } int main(){ n = read(), m = read(); for(int i = 1; i <= n; i++) a[i] = read(); memset(minn, -1, sizeof tag); build(1, 1, n); for(int i = 1; i <= m; i++){ int d = read(), s = read(), t = read(); if(s > t) swap(s, t); // cout<<s<<" "<<t<<" "<<query(1, 1, n, s, t)<<"!!!"<<endl; if(query(1, 1, n, s, t) < d){ wr(-1), putchar(‘\n‘), wr(i); return 0; } modify(1, 1, n, s, t, d); } wr(0); return 0; }
积木大赛
简单分析
#include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<string> #include<algorithm> #include<cmath> using namespace std; const int N = 1e5 + 5; int n, ans, last; int main(){ cin >> n; for(int i = 1; i <= n; i++){ int tmp; cin >> tmp; if(tmp - last > 0) ans += tmp - last; last = tmp; } cout << ans; return 0; }
Vigenère密码
简单分析 + 模拟
#include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<string> #include<algorithm> #include<cmath> using namespace std; int klen, slen, key[1005]; char k[1005], s[1005], t[1005]; int main(){ cin >> k >> s; klen = strlen(k), slen = strlen(s); for(int i = 0; i < klen; i++){ if(‘a‘ <= k[i] && k[i] <= ‘z‘) key[i] = k[i] - ‘a‘; else key[i] = k[i] - ‘A‘; } for(int i = 0; i < slen; i++){ if(‘a‘ <= s[i] && s[i] <= ‘z‘){ t[i] = s[i] - key[i % (klen)]; while(t[i] < ‘a‘) t[i] += 26; } else if(‘A‘ <= s[i] && s[i] <= ‘Z‘){ t[i] = s[i] - key[i % (klen)]; while(t[i] < ‘A‘) t[i] += 26; } else continue; putchar(t[i]); } return 0; }
花匠
动态规划 + 树状数组优化
#include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<string> #include<algorithm> #include<cmath> using namespace std; const int N = 1e5 + 5, H = 1e6 + 5; int n, h[N], f[N], g[N], maxh, maxxF[H], maxxG[H], ans; inline int read(){ int i = 0, f = 1; char ch = getchar(); for(; (ch < ‘0‘ || ch > ‘9‘) && ch != ‘-‘; ch = getchar()); if(ch == ‘-‘) f = -1, ch = getchar(); for(; ch >= ‘0‘ && ch <= ‘9‘; ch = getchar()) i = (i << 3) + (i << 1) + (ch - ‘0‘); return i * f; } inline void wr(int x){ if(x < 0) putchar(‘-‘), x = -x; if(x > 9) wr(x / 10); putchar(x % 10 + ‘0‘); } inline void uptF(int x, int v){ for(int i = x; i <= maxh; i += (i&(-i))) maxxF[i] = max(maxxF[i], v); } inline void uptG(int x, int v){ for(int i = x; i <= maxh; i += (i&(-i))) maxxG[i] = max(maxxG[i], v); } inline int queryF(int x){ int ret = 0; for(int i = x; i > 0; i-=(i&-i)) ret = max(maxxF[i], ret); return ret; } inline int queryG(int x){ int ret = 0; for(int i = x; i > 0; i-=(i&-i)) ret = max(ret, maxxG[i]); return ret; } int main(){ n = read(); for(int i = 1; i <= n; i++) h[i] = read() + 1, maxh = max(maxh, h[i]); maxh += 5; for(int i = 1; i <= n; i++){ f[i] = max(queryG(h[i] - 1) + 1, f[i]); g[i] = max(queryF(maxh - h[i] - 1) + 1, g[i]); uptF(maxh - h[i], f[i]); uptG(h[i], g[i]); ans = max(ans, max(f[i], g[i])); } wr(ans); return 0; }
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