Topic links: https://atcoder.jp/contests/abc128/tasks/abc128_e
Subject to the effect
In a road (road which can be seen as coordinate axes x-axis direction from zero to positive infinity direction rays), there are N road works, road works represented by each triad $ (S_i, T_i, X_i) $ , meaning that the i-th road works at the point $ $ S_i time starts at $ T_i $ completely over time (duration of the interval does not include $ T_i $), the construction site is in the $ X_i $ x-axis position. During the construction works the same place, their time will not overlap. Q There are personal turn at a speed of one meter per second in the point $ $ D_i time from origin, met under construction and stopped the project does not go, ask everyone finally came to a stop position, if not stop, the output -1.
analysis
For the i-th project $ (S_i, T_i, X_i) $, only for departure time $ [S_i - X_i, T_i - X_i) who will play in the $ range blocking action, so for everyone, we only We need to find can play a role in blocking his position and construction engineering frontmost position on the line.
For every $ D_i $, and his works are related to those already beginning but not the end, in order to pick out the location of all of these projects, we can construct a triplet $ event (t_i, x_i, d_i) $, is defined as follows :
- $d_i \in \{0, 1\}$。
- This $ d_i = 0 $ o'clock, $ t_i = S_i - X_i $.
- This $ d_i = 1 $ o'clock, $ t_i = T_i - X_i $.
- $x_i = X_i$。
Then using a set of dedicated storage and related to the current $ $ $ D_i X_i $, $ t_i the triplet sequence in accordance with a $ row, then sequentially through all $ t_i \ leq D_i $ event, if $ d_i = 0 $, on the $ x_i $ to the collection, otherwise it is deleted from the collection.
Then set the minimum position is the current position of the people stay.
code show as below
1 #include <bits/stdc++.h> 2 using namespace std; 3 4 #define INIT() ios::sync_with_stdio(false);cin.tie(0);cout.tie(0); 5 #define Rep(i,n) for (int i = 0; i < (n); ++i) 6 #define For(i,s,t) for (int i = (s); i <= (t); ++i) 7 #define rFor(i,t,s) for (int i = (t); i >= (s); --i) 8 #define ForLL(i, s, t) for (LL i = LL(s); i <= LL(t); ++i) 9 #define rForLL(i, t, s) for (LL i = LL(t); i >= LL(s); --i) 10 #define foreach(i,c) for (__typeof(c.begin()) i = c.begin(); i != c.end(); ++i) 11 #define rforeach(i,c) for (__typeof(c.rbegin()) i = c.rbegin(); i != c.rend(); ++i) 12 13 #define pr(x) cout << #x << " = " << x << " " 14 #define prln(x) cout << #x << " = " << x << endl 15 16 #define LOWBIT(x) ((x)&(-x)) 17 18 #define ALL(x) x.begin(),x.end() 19 #define INS(x) inserter(x,x.begin()) 20 21 #define ms0(a) memset(a,0,sizeof(a)) 22 #define msI(a) memset(a,inf,sizeof(a)) 23 #define msM(a) memset(a,-1,sizeof(a)) 24 25 #define MP make_pair 26 #define PB push_back 27 #define ft first 28 #define sd second 29 30 template<typename T1, typename T2> 31 istream &operator>>(istream &in, pair<T1, T2> &p) { 32 in >> p.first >> p.second; 33 return in; 34 } 35 36 template<typename T> 37 istream &operator>>(istream &in, vector<T> &v) { 38 for (auto &x: v) 39 in >> x; 40 return in; 41 } 42 43 template<typename T1, typename T2> 44 ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) { 45 out << "[" << p.first << ", " << p.second << "]" << "\n"; 46 return out; 47 } 48 49 inline int gc(){ 50 static const int BUF = 1e7; 51 static char buf[BUF], *bg = buf + BUF, *ed = bg; 52 53 if(bg == ed) fread(bg = buf, 1, BUF, stdin); 54 return *bg++; 55 } 56 57 inline int ri(){ 58 int x = 0, f = 1, c = gc(); 59 for(; c<48||c>57; f = c=='-'?-1:f, c=gc()); 60 for(; c>47&&c<58; x = x*10 + c - 48, c=gc()); 61 return x*f; 62 } 63 64 typedef long long LL; 65 typedef unsigned long long uLL; 66 typedef pair< double, double > PDD; 67 typedef pair< int, int > PII; 68 typedef pair< string, int > PSI; 69 typedef set< int > SI; 70 typedef vector< int > VI; 71 typedef vector< PII > VPII; 72 typedef map< int, int > MII; 73 typedef multimap< int, int > MMII; 74 typedef unordered_map< int, int > uMII; 75 typedef pair< LL, LL > PLL; 76 typedef vector< LL > VL; 77 typedef vector< VL > VVL; 78 typedef priority_queue< int > PQIMax; 79 typedef priority_queue< int, VI, greater< int > > PQIMin; 80 const double EPS = 1e-10; 81 const LL inf = 0x7fffffff; 82 const LL infLL = 0x7fffffffffffffffLL; 83 const LL mod = 1e9 + 7; 84 const int maxN = 2e5 + 7; 85 const LL ONE = 1; 86 const LL evenBits = 0xaaaaaaaaaaaaaaaa; 87 const LL oddBits = 0x5555555555555555; 88 89 struct Tuple{ 90 int T, X, D; 91 92 inline bool operator< (const Tuple &x) const{ 93 return T < x.T; 94 } 95 }; 96 97 int N, Q; 98 Tuple event[maxN << 1]; 99 int len; 100 multiset< int > msi; 101 102 int main(){ 103 //INIT(); 104 N = ri(); 105 Q = ri(); 106 For(i, 1, N) { 107 int S, T, X; 108 S = ri(); 109 T = ri(); 110 X = ri(); 111 112 event[++len].T = S - X; 113 event[len].X = X; 114 event[len].D = 1; 115 116 event[++len].T = T - X; 117 event[len].X = X; 118 event[len].D = 0; 119 } 120 sort(event + 1, event + len + 1); 121 122 int k = 1, D; 123 For(i, 1, Q) { 124 D = ri(); 125 //******************************************************************** 126 while(k <= len) { 127 if(event[k].T <= D) { 128 if(event[k].D) msi.insert(event[k].X); 129 else msi.erase(msi.find(event[k].X)); 130 ++k; 131 } 132 else BREAK ; 133 } 134 135 / * 136 lesson of blood, at first I was not writing a while loop, but for cycling, seemingly no problem 137 but has been submitted by a timeout, because some cases makes the else branch has not been implemented to, Thus the time complexity to surge 138 affixed error code, warning 139 the For (J, K, len) { 140 IF (Event [J] .T <= D) { 141 is IF (Event [J] II.D ) msi.insert (Event [J] .X); 142 the else msi.erase (msi.find (Event [J] .X)); 143 ++ K; 144 } 145 the else { 146 K = J; 147 BREAK; 148 } 149 } 150 */ 151 152 //******************************************************************** 153 154 int ans = -1; 155 if(msi.size()) ans = *msi.begin(); 156 printf("%d\n", ans); 157 } 158 return 0; 159 }