37 lines
907 B
C++
37 lines
907 B
C++
#include <iostream>
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#include <tuple>
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#include <cmath>
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#include <vector>
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#include <algorithm>
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using namespace std;
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//tuple(t, x, y)
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int dist(const tuple<int, int, int>& i, const tuple<int, int, int>& j){
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return ( abs(get<1>(i) - get<1>(j)) + abs(get<2>(i) - get<2>(j)) );
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}
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int time(const tuple<int, int, int>& i, const tuple<int, int, int>& j){
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return abs( get<0>(i) - get<0>(j) );
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}
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int main(){
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int n, m;
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cin >> n >> m;
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//n * n, m 个鼹鼠
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vector<tuple<int, int, int>> ham(m);
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vector<int> dp(m, 1);
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for(int i = 0; i < m; i++){
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int t, x, y;
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cin >> t >> x >> y;
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ham[i] = make_tuple(t, x, y);
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}
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//dp[m] = max (能走到的(t2 - t1 > dist)dp[x] + 1)
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for(int i = 1; i < m; i++){
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for(int j = 0; j < i; j++){
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//如果能走到就更新
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if(dist(ham[i], ham[j]) <= time(ham[i], ham[j])){
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dp[i] = max(dp[i], dp[j] + 1);
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}
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}
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}
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cout << *max_element(dp.begin(), dp.end()) << endl;
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return 0;
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}
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