Submission #609287

#	Time	Username	Problem	Language	Result	Execution time	Memory
609287		MohammadAghil	Dynamic Diameter (CEOI19_diameter)	C++17	7 / 100	5102 ms	299556 KiB

diameter

      #include <bits/stdc++.h>
//   #pragma GCC optimize ("Ofast,unroll-loops")
// #pragma GCC target ("avx2")
    using namespace std;
  typedef long long ll;
   typedef pair<ll, ll> pp;
    #define er(args ...) cerr << __LINE__ << ": ", err(new istringstream(string(#args)), args), cerr << endl
      #define per(i,r,l) for(int i = (r); i >= (l); i--)
        #define rep(i,l,r) for(int i = (l); i < (r); i++)
           #define all(x) begin(x), end(x)
              #define sz(x) (int)(x).size()
                  #define pb push_back
                      #define ss second
                           #define ff first
                                   void err(istringstream *iss){}template<typename T,typename ...Args> void err(istringstream *iss,const T &_val, const Args&...args){string _name;*iss>>_name;if(_name.back()==',')_name.pop_back();cerr<<_name<<" = "<<_val<<", ",err(iss,args...);}
void IOS(){
     cin.tie(0) -> sync_with_stdio(0);
     // #ifndef ONLINE_JUDGE
     //      freopen("in.in", "r", stdin);
     //      freopen("out.out", "w", stdout);
     // #endif
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll mod = 1e9 + 7, maxn = 1e5 + 5, lg = 22, inf = ll(1e18) + 5;
ll pw(ll a,ll b,ll md=mod){if(!b)return 1;ll k=pw(a,b>>1ll);return k*k%md*(b&1ll?a:1)%md;}

struct Segment{
     vector<ll> laz, seg;
     int n;
     Segment(){}
     Segment(vector<ll> a): n(sz(a)){
          laz.assign(n<<2, 0), seg.assign(n<<2, 0);
          build(1, 0, n, a);
     }
     void build(int x, int lx, int rx, vector<ll>& a){
          if(lx + 1 == rx){
               seg[x] = a[lx];
               return;
          }
          int mid = (lx + rx)>>1;
          build(x<<1, lx, mid, a), build(x<<1|1, mid, rx, a);
          seg[x] = max(seg[x<<1], seg[x<<1|1]);
     }
     void updNode(int x, ll k){
          seg[x] += k, laz[x] += k;
     }
     void shift(int x){
          if(laz[x]){
               updNode(x<<1, laz[x]);
               updNode(x<<1|1, laz[x]);
               laz[x] = 0;
          }
     }
     void upd(int l, int r, ll k, int x, int lx, int rx){
          if(l <= lx && r >= rx){
               updNode(x, k);
               return;
          } 
          shift(x);
          int mid = (lx + rx)>>1;
          if(l < mid) upd(l, r, k, x<<1, lx, mid);
          if(mid < r) upd(l, r, k, x<<1|1, mid, rx);
          seg[x] = max(seg[x<<1], seg[x<<1|1]);
     }
     void upd(int l, int r, ll k){ upd(l, r, k, 1, 0, n); }
     ll get(int l, int r, int x, int lx, int rx){
          if(l <= lx && r >= rx) return seg[x];
          shift(x);
          int mid = (lx + rx)>>1;
          ll res = 0;
          if(l < mid) res = get(l, r, x<<1, lx, mid);
          if(mid < r) res = max(res, get(l, r, x<<1|1, mid, rx));
          return res;
     }
     ll get(int l, int r){ return get(l, r, 1, 0, n); }
} seg[maxn];

struct CHSegment{
     vector<ll> seg;
     int n;
     CHSegment(){}
     CHSegment(int n): n(n){
          seg.assign(n<<1, 0);
     }
     void upd(int i, ll k){
          for(i += n, seg[i] = k; i > 1; i >>= 1) seg[i>>1] = max(seg[i], seg[i^1]);
     }
     ll get(int l, int r){
          ll res = 0;
          for(l += n, r += n; l < r; l >>= 1, r >>= 1){
               if(l&1) res = max(res, seg[l++]);
               if(r&1) res = max(res, seg[--r]);
          }
          return res;
     }
};

struct CHSegment2{
     vector<pp> seg;
     int n;
     pp comb(pp a, pp b){
          if(a.ff < b.ff) swap(a, b);
          return {a.ff, max(a.ss, b.ff)};
     }
     CHSegment2(){}
     CHSegment2(int n): n(n){
          seg.assign(n<<1, {0, 0});
     }
     void upd(int i, ll k){
          for(i += n, seg[i] = {k, 0}; i > 1; i >>= 1) seg[i>>1] = comb(seg[i], seg[i^1]);
     }
     pp get(int l, int r){
          pp res = {0, 0};
          for(l += n, r += n; l < r; l >>= 1, r >>= 1){
               if(l&1) res = comb(res, seg[l++]);
               if(r&1) res = comb(res, seg[--r]);
          }
          return res;
     }
};

int cnt[maxn], par[maxn];
vector<pair<int, ll>> adj[maxn];
map<int, int> st[maxn], en[maxn], id[maxn]; int t;
bool ban[maxn];
CHSegment2 mx[maxn];

#define chk (c-p&&ban[c]^1)

void dfs(int r, int p){
     cnt[r] = 1;
     for(auto[c, d]: adj[r]) if(chk){
          dfs(c, r);
          cnt[r] += cnt[c];
     }
}

int find_center(int r, int p, int tot){
     for(auto[c, d]: adj[r]) if(chk && (cnt[c]<<1) > tot) return find_center(c, r, tot);
     return r;
}

vector<ll> tmp;
ll Dist[maxn];
void dfs2(int r, int p, int cen, ll dist, int ref){
     if(p == cen) ref = r;
     Dist[r] = 0;
     id[cen][r] = ref;
     tmp.pb(dist);
     st[cen][r] = t++;
     for(auto[c, d]: adj[r]) if(chk) dfs2(c, r, cen, dist + d, ref), Dist[r] = max(Dist[r], Dist[c] + d);
     en[cen][r] = t;
}

void reset(int r){
     ban[r] = true;
     t = 0;
     tmp.clear();
}

void dec(int r, int p = -1){
     dfs(r, -1);
     r = find_center(r, -1, cnt[r]);
     par[r] = p;
     dfs2(r, -1, r, 0, r);
     seg[r] = Segment(tmp);
     mx[r] = CHSegment2(t);
     reset(r);
     for(auto[c, d]: adj[r]) if(ban[c]^1) {
          dec(c, r);
          mx[r].upd(st[r][c], Dist[c] + d);
     }
}

CHSegment ans;
ll get_ans(){
     return ans.seg[1];
}

ll get(int r){
     return mx[r].seg[1].ff + mx[r].seg[1].ss;
}

void upd(int u, int v, ll delta){
     auto lis = [&](int u){
          vector<int> res;
          while(u + 1) res.pb(u), u = par[u];
          return res;
     };
     vector<int> lsu = lis(u), lsv = lis(v);
     reverse(all(lsu)), reverse(all(lsv));
     vector<int> cand;
     rep(i,0,min(sz(lsu), sz(lsv))){
          if(lsu[i] - lsv[i]) break;
          cand.pb(lsu[i]); 
     }
     for(int r: cand){
          if(st[r][u] > st[r][v]) swap(u, v);
          int ref = id[r][v];
          
          seg[r].upd(st[r][v], en[r][v], delta);

          mx[r].upd(st[r][ref], seg[r].get(st[r][ref], en[r][ref]));
          ans.upd(r, get(r));
     }
}

pp edge[maxn];
ll vl[maxn];
int main(){ IOS();
     int n, q; cin >> n >> q;
     ll W; cin >> W;
     rep(i,0,n-1){
          int u, v; cin >> u >> v; u--, v--; 
          ll w; cin >> w;
          adj[u].pb({v, w}), adj[v].pb({u, w});
          edge[i] = {u, v}, vl[i] = w;
     } 
     
     ans = CHSegment(n);
     dec(0);
     rep(i,0,n) ans.upd(i, get(i));

     ll lst = 0;
     while(q--){
          ll d, e; cin >> d >> e;
          d = (d + lst)%(n-1), e = (e + lst)%W;
          upd(edge[d].ff, edge[d].ss, e - vl[d]);
          vl[d] = e;
          cout << (lst = get_ans()) << '\n';
     }
     return 0; 
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 13
• Subtask 3: 7 / 7
• Subtask 4: 0 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 27