#include <bits/stdc++.h> using namespace std; #define REP(i,a,b) for (int i = (a); i <= (b); ++i) #define REPD(i,a,b) for (int i = (a); i >= (b); --i) #define FORI(i,n) REP(i,1,n) #define FOR(i,n) REP(i,0,int(n)-1) #define mp make_pair #define pb push_back #define sz(x) int((x).size()) #define dbg(v) cerr << #v << " = " << (v) << endl; #define FOREACH(i,t) for (__typeof(t.begin()) i = t.begin(); i != t.end(); ++i) #define fi first #define se second typedef pair<int,int> pii; typedef vector<int> vi; typedef long long ll; const ll INF = 10000000000000LL; const int MAXN = 500100; vector<int> g[MAXN]; int p[MAXN]; int a[MAXN]; int b[MAXN]; int n,m; int r; int lvl[MAXN]; vector<int> lvlV[MAXN]; int maxLvl; void rootTree(int root) { r = root; p[r] = -1; lvl[r] = 0; maxLvl = 0; lvlV[0].pb(r); queue<int> q; q.push(r); while (!q.empty()) { int v = q.front(); q.pop(); FOR(i, g[v].size()) { int v2 = g[v][i]; if (v2 == p[v]) continue; p[v2] = v; lvl[v2] = lvl[v] + 1; if (lvl[v2] > maxLvl) maxLvl = lvl[v2]; lvlV[lvl[v2]].pb(v2); q.push(v2); } } } bool isLeaf(int v) { return g[v].size() == 1; } int main() { scanf("%d %d", &n, &m); FOR(i,n-1) { int x,y; scanf("%d %d", &x, &y); x--; y--; g[x].pb(y); g[y].pb(x); } FOR(i,m) { int x; scanf("%d", &x); a[i] = x; b[i] = x; } //special case if (m==n && n==2) { int res = a[0]-a[1]; if (res < 0) res = -1*res; printf("%d\n", res); return 0; } rootTree(m); ll result = 0; for(int i=maxLvl;i>=0;i--) { FOR(j, lvlV[i].size()) { int v = lvlV[i][j]; if (isLeaf(v)) continue; //consider children of v -> make interval problem vector<int> children; FOR(k, g[v].size()) { int v2 = g[v][k]; if (p[v] != v2) { children.pb(v2); } } //solve Interval problem vector<pair<int, bool> > endPoints; //x, start=false ll d=0; FOR(k, children.size()) { int v2 = children[k]; endPoints.pb(mp(a[v2],false)); endPoints.pb(mp(b[v2],true)); d += a[v2]; } sort(endPoints.begin(), endPoints.end()); int pos = 0; int left = 0; int right = children.size(); ll bestD = INF; int bestA,bestB; bestA = bestB = 0; FOR(k, endPoints.size()) { pair<int, bool> event = endPoints[k]; int x = event.first; bool ending = event.second; ll dx = x-pos; d += (left-right)*dx; pos = x; if (d<bestD) { bestD = d; bestA = bestB = pos; } if (d==bestD) { bestB = pos; } if (ending) left++; else right--; } a[v] = bestA; b[v] = bestB; result += bestD; } } printf("%lld\n", result); 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 | #include <bits/stdc++.h> using namespace std; #define REP(i,a,b) for (int i = (a); i <= (b); ++i) #define REPD(i,a,b) for (int i = (a); i >= (b); --i) #define FORI(i,n) REP(i,1,n) #define FOR(i,n) REP(i,0,int(n)-1) #define mp make_pair #define pb push_back #define sz(x) int((x).size()) #define dbg(v) cerr << #v << " = " << (v) << endl; #define FOREACH(i,t) for (__typeof(t.begin()) i = t.begin(); i != t.end(); ++i) #define fi first #define se second typedef pair<int,int> pii; typedef vector<int> vi; typedef long long ll; const ll INF = 10000000000000LL; const int MAXN = 500100; vector<int> g[MAXN]; int p[MAXN]; int a[MAXN]; int b[MAXN]; int n,m; int r; int lvl[MAXN]; vector<int> lvlV[MAXN]; int maxLvl; void rootTree(int root) { r = root; p[r] = -1; lvl[r] = 0; maxLvl = 0; lvlV[0].pb(r); queue<int> q; q.push(r); while (!q.empty()) { int v = q.front(); q.pop(); FOR(i, g[v].size()) { int v2 = g[v][i]; if (v2 == p[v]) continue; p[v2] = v; lvl[v2] = lvl[v] + 1; if (lvl[v2] > maxLvl) maxLvl = lvl[v2]; lvlV[lvl[v2]].pb(v2); q.push(v2); } } } bool isLeaf(int v) { return g[v].size() == 1; } int main() { scanf("%d %d", &n, &m); FOR(i,n-1) { int x,y; scanf("%d %d", &x, &y); x--; y--; g[x].pb(y); g[y].pb(x); } FOR(i,m) { int x; scanf("%d", &x); a[i] = x; b[i] = x; } //special case if (m==n && n==2) { int res = a[0]-a[1]; if (res < 0) res = -1*res; printf("%d\n", res); return 0; } rootTree(m); ll result = 0; for(int i=maxLvl;i>=0;i--) { FOR(j, lvlV[i].size()) { int v = lvlV[i][j]; if (isLeaf(v)) continue; //consider children of v -> make interval problem vector<int> children; FOR(k, g[v].size()) { int v2 = g[v][k]; if (p[v] != v2) { children.pb(v2); } } //solve Interval problem vector<pair<int, bool> > endPoints; //x, start=false ll d=0; FOR(k, children.size()) { int v2 = children[k]; endPoints.pb(mp(a[v2],false)); endPoints.pb(mp(b[v2],true)); d += a[v2]; } sort(endPoints.begin(), endPoints.end()); int pos = 0; int left = 0; int right = children.size(); ll bestD = INF; int bestA,bestB; bestA = bestB = 0; FOR(k, endPoints.size()) { pair<int, bool> event = endPoints[k]; int x = event.first; bool ending = event.second; ll dx = x-pos; d += (left-right)*dx; pos = x; if (d<bestD) { bestD = d; bestA = bestB = pos; } if (d==bestD) { bestB = pos; } if (ending) left++; else right--; } a[v] = bestA; b[v] = bestB; result += bestD; } } printf("%lld\n", result); return 0; } |