题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=16
像套娃一样把矩形套起来。先给矩形从小到大排序，然后做最长上升子序列就行
1 /* 2 ━━━━━┒ギリギリ♂ eye！ 3 ┓┏┓┏┓┃キリキリ♂ mind！ 4 ┛┗┛┗┛┃＼○／ 5 ┓┏┓┏┓┃ / 6 ┛┗┛┗┛┃ノ) 7 ┓┏┓┏┓┃ 8 ┛┗┛┗┛┃ 9 ┓┏┓┏┓┃ 10 ┛┗┛┗┛┃ 11 ┓┏┓┏┓┃ 12 ┛┗┛┗┛┃ 13 ┓┏┓┏┓┃ 14 ┃┃┃┃┃┃ 15 ┻┻┻┻┻┻ 16 */ 17 #include <algorithm> 18 #include <iostream> 19 #include <iomanip> 20 #include <cstring> 21 #include <climits> 22 #include <complex> 23 #include <fstream> 24 #include <cassert> 25 #include <cstdio> 26 #include <bitset> 27 #include <vector> 28 #include <deque> 29 #include <queue> 30 #include <stack> 31 #include <ctime> 32 #include <set> 33 #include <map> 34 #include <cmath> 35 using namespace std; 36 #define fr first 37 #define sc second 38 #define cl clear 39 #define BUG puts("here!!!") 40 #define W(a) while(a--) 41 #define pb(a) push_back(a) 42 #define Rint(a) scanf("%d", &a) 43 #define Rll(a) scanf("%I64d", &a) 44 #define Rs(a) scanf("%s", a) 45 #define Cin(a) cin >> a 46 #define FRead() freopen("in", "r", stdin) 47 #define FWrite() freopen("out", "w", stdout) 48 #define Rep(i, len) for(LL i = 0; i < (len); i++) 49 #define For(i, a, len) for(LL i = (a); i < (len); i++) 50 #define Cls(a) memset((a), 0, sizeof(a)) 51 #define Clr(a, x) memset((a), (x), sizeof(a)) 52 #define Fuint(a) memset((a), 0x7f7f, sizeof(a)) 53 #define lrt rt << 1 54 #define rrt rt << 1 | 1 55 #define pi 3.14159265359 56 #define RT return 57 #define lowbit(x) x & (-x) 58 #define onenum(x) __builtin_popcount(x) 59 typedef long long LL; 60 typedef long double LD; 61 typedef unsigned long long Uint; 62 typedef pair<LL, LL> pii; 63 typedef pair<string, LL> psi; 64 typedef map<string, LL> msi; 65 typedef vector<LL> vi; 66 typedef vector<LL> vl; 67 typedef vector<vl> vvl; 68 typedef vector<bool> vb; 69 70 typedef struct Square { 71 int x, y; 72 Square() {} 73 Square(int xx, int yy) : x(xx), y(yy) {} 74 }Square; 75 76 const int maxn = 1010; 77 Square s[maxn]; 78 int n; 79 int dp[maxn]; 80 81 bool cmp(Square a, Square b) { 82 if(a.x == b.x) return a.y <= b.y; 83 return a.x < b.x; 84 } 85 86 bool ok(Square a, Square b) { 87 return a.x > b.x && a.y > b.y; 88 } 89 90 int main() { 91 // FRead(); 92 int T, x, y; 93 Rint(T); 94 W(T) { 95 Cls(dp); 96 Rint(n); 97 For(i, 1, n+1) { 98 Rint(x); Rint(y); 99 if(x > y) swap(x, y); 100 s[i] = Square(x, y); 101 } 102 sort(s+1, s+n+1, cmp); 103 int ret = 0; 104 For(i, 2, n+1) { 105 dp[i] = 0; 106 For(j, 1, i+1) { 107 if(ok(s[i], s[j])) { 108 dp[i] = max(dp[i], dp[j]+1); 109 } 110 } 111 ret = max(dp[i], ret); 112 } 113 printf("%d ", ret+1); 114 } 115 RT 0; 116 }