#define NDEBUG #include <cstdio> #include <cstdlib> #include <algorithm> #include <vector> #include <set> #include <cassert> using namespace std; using ll = long long; using range = pair<int, int>; #define MAXX 500001 int n, m; vector<int> E[MAXX]; int UnsolvedAdj[MAXX]; range SolutionRanges[MAXX]; struct CmpStations { bool operator () (int s1, int s2); }; set<int, CmpStations> Q; int Values[MAXX]; vector<int> NoValueStations; int Out[MAXX]; void Read(); void PrepareQ(); void ProcessQ(); void SpecifyValues(); void CalcAndPrintResult(); int main() { Read(); PrepareQ(); ProcessQ(); SpecifyValues(); CalcAndPrintResult(); return 0; } void Read() { scanf("%d%d", &n, &m); for(int i = 1; i < n; ++i) { int v, u; scanf("%d%d", &v, &u); E[v].push_back(u); E[u].push_back(v); if(v > m) ++UnsolvedAdj[u]; if(u > m) ++UnsolvedAdj[v]; } for(int i = 1; i <= m; ++i) { int r; scanf("%d", &r); SolutionRanges[i] = {r, r}; Values[i] = r; } } void PrepareQ() { for(int i = m+1; i <= n; ++i) Q.insert(i); } void ProcessQ() { while(!Q.empty()) { auto first = Q.begin(); auto station = *first; Q.erase(first); assert(UnsolvedAdj[station] < 2); vector<int> rangeValuesBase; for(auto adjStation : E[station]) { auto& adjSolutionRange = SolutionRanges[adjStation]; if(adjSolutionRange.first == 0) { assert(Q.find(adjStation) != Q.end()); Q.erase(adjStation); --UnsolvedAdj[adjStation]; Q.insert(adjStation); assert(Out[station] == 0); Out[station] = adjStation; } else { rangeValuesBase.push_back(adjSolutionRange.first); rangeValuesBase.push_back(adjSolutionRange.second); } } sort(rangeValuesBase.begin(), rangeValuesBase.end()); auto rangeSecondI = rangeValuesBase.size() / 2; auto rangeFirstI = rangeSecondI - 1; auto rangeFirst = rangeValuesBase[rangeFirstI]; auto rangeSecond = rangeValuesBase[rangeSecondI]; assert(rangeFirst <= rangeSecond); SolutionRanges[station] = {rangeFirst, rangeSecond}; if(rangeFirst != rangeSecond) NoValueStations.push_back(station); else Values[station] = rangeFirst; } reverse(NoValueStations.begin(), NoValueStations.end()); } void SpecifyValues() { for(auto station : NoValueStations) { auto& stationRange = SolutionRanges[station]; if(Out[station] == 0) { Values[station] = stationRange.first; } else { auto value = Values[Out[station]]; if(value > stationRange.second) value = stationRange.second; else if(value < stationRange.first) value = stationRange.first; Values[station] = value; } } } void CalcAndPrintResult() { ll result = 0ll; for(int i = 1; i <= n; ++i) { assert(Values[i] > 0); for(auto adj : E[i]) result += (ll)abs(Values[i] - Values[adj]); } printf("%lld", result / 2); } inline bool CmpStations::operator () (int s1, int s2) { return UnsolvedAdj[s1] == UnsolvedAdj[s2] ? s1 < s2 : UnsolvedAdj[s1] < UnsolvedAdj[s2]; }
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 | #define NDEBUG #include <cstdio> #include <cstdlib> #include <algorithm> #include <vector> #include <set> #include <cassert> using namespace std; using ll = long long; using range = pair<int, int>; #define MAXX 500001 int n, m; vector<int> E[MAXX]; int UnsolvedAdj[MAXX]; range SolutionRanges[MAXX]; struct CmpStations { bool operator () (int s1, int s2); }; set<int, CmpStations> Q; int Values[MAXX]; vector<int> NoValueStations; int Out[MAXX]; void Read(); void PrepareQ(); void ProcessQ(); void SpecifyValues(); void CalcAndPrintResult(); int main() { Read(); PrepareQ(); ProcessQ(); SpecifyValues(); CalcAndPrintResult(); return 0; } void Read() { scanf("%d%d", &n, &m); for(int i = 1; i < n; ++i) { int v, u; scanf("%d%d", &v, &u); E[v].push_back(u); E[u].push_back(v); if(v > m) ++UnsolvedAdj[u]; if(u > m) ++UnsolvedAdj[v]; } for(int i = 1; i <= m; ++i) { int r; scanf("%d", &r); SolutionRanges[i] = {r, r}; Values[i] = r; } } void PrepareQ() { for(int i = m+1; i <= n; ++i) Q.insert(i); } void ProcessQ() { while(!Q.empty()) { auto first = Q.begin(); auto station = *first; Q.erase(first); assert(UnsolvedAdj[station] < 2); vector<int> rangeValuesBase; for(auto adjStation : E[station]) { auto& adjSolutionRange = SolutionRanges[adjStation]; if(adjSolutionRange.first == 0) { assert(Q.find(adjStation) != Q.end()); Q.erase(adjStation); --UnsolvedAdj[adjStation]; Q.insert(adjStation); assert(Out[station] == 0); Out[station] = adjStation; } else { rangeValuesBase.push_back(adjSolutionRange.first); rangeValuesBase.push_back(adjSolutionRange.second); } } sort(rangeValuesBase.begin(), rangeValuesBase.end()); auto rangeSecondI = rangeValuesBase.size() / 2; auto rangeFirstI = rangeSecondI - 1; auto rangeFirst = rangeValuesBase[rangeFirstI]; auto rangeSecond = rangeValuesBase[rangeSecondI]; assert(rangeFirst <= rangeSecond); SolutionRanges[station] = {rangeFirst, rangeSecond}; if(rangeFirst != rangeSecond) NoValueStations.push_back(station); else Values[station] = rangeFirst; } reverse(NoValueStations.begin(), NoValueStations.end()); } void SpecifyValues() { for(auto station : NoValueStations) { auto& stationRange = SolutionRanges[station]; if(Out[station] == 0) { Values[station] = stationRange.first; } else { auto value = Values[Out[station]]; if(value > stationRange.second) value = stationRange.second; else if(value < stationRange.first) value = stationRange.first; Values[station] = value; } } } void CalcAndPrintResult() { ll result = 0ll; for(int i = 1; i <= n; ++i) { assert(Values[i] > 0); for(auto adj : E[i]) result += (ll)abs(Values[i] - Values[adj]); } printf("%lld", result / 2); } inline bool CmpStations::operator () (int s1, int s2) { return UnsolvedAdj[s1] == UnsolvedAdj[s2] ? s1 < s2 : UnsolvedAdj[s1] < UnsolvedAdj[s2]; } |