这场练练golang
题目链接：https://codeforces.com/contest/1296
A：
白给
1 package main
2
3 import "fmt"
4
5 const (
6 maxn = 2010
7 )
8
9 var (
10 a [maxn]int
11 n, t int
12 )
13
14 func main() {
15 fmt.Scan(&t)
16 for cnt := 1; cnt <= t; cnt++ {
17 var odd, even int
18 fmt.Scan(&n)
19 for i := 1; i <= n; i++ {
20 var x int
21 fmt.Scan(&x)
22 if x&1 != 0 {
23 odd++
24 } else {
25 even++
26 }
27 }
28 if odd == 0 {
29 fmt.Println("NO")
30 } else if even == 0 {
31 if n&1 != 0 {
32 fmt.Println("YES")
33 } else {
34 fmt.Println("NO")
35 }
36 } else {
37 fmt.Println("YES")
38 }
39 }
40 }
B：
注意每次给钱时保留个位不要给就行
1 package main
2
3 import "fmt"
4
5 var (
6 t int
7 )
8
9 func main() {
10 fmt.Scan(&t)
11 for cnt := 1; cnt <= t; cnt++ {
12 var s, ans, tmp int
13 fmt.Scan(&s)
14 tmp = s
15 for {
16 var refound, yu = tmp / 10, tmp % 10
17 ans += refound * 10
18 if tmp < 10 {
19 ans += tmp
20 break
21 }
22 tmp = refound + yu
23 }
24 fmt.Println(ans)
25 }
26 }
C：
做偏移量(x,y)到字符串下标的映射即可
1 package main
2
3 import "fmt"
4
5 const maxn int = 2e5 + 10
6
7 type pair struct {
8 fir, sec int
9 }
10
11 var t int
12
13 func main() {
14 fmt.Scan(&t)
15 for ; t > 0; t-- {
16 var n int
17 var s string
18 fmt.Scan(&n, &s)
19 s = " " + s
20 var ans, l, r, x, y = n + 1, 0, 0, 0, 0
21 m := make(map[pair]int)
22 m[pair{0, 0}] = 1
23 for i := 1; i < len(s); i++ {
24 switch s[i] {
25 case 'L':
26 x--
27 case 'R':
28 x++
29 case 'U':
30 y++
31 case 'D':
32 y--
33 }
34 v := m[pair{x, y}]
35 if v != 0 {
36 if ans > (i - v + 1) {
37 ans = i - v + 1
38 l = v
39 r = i
40 }
41 }
42 m[pair{x, y}] = i + 1
43 }
44 if ans == (n + 1) {
45 fmt.Println("-1")
46 } else {
47 fmt.Println(l, r)
48 }
49 }
50 }
D：
对每个数，模a+b之后计算余数要a攻击次数，再O(n)贪心即可
1 /* basic header */
2 #include <bits/stdc++.h>
3 /* define */
4 #define ll long long
5 #define dou double
6 #define pb emplace_back
7 #define mp make_pair
8 #define sot(a,b) sort(a+1,a+1+b)
9 #define rep1(i,a,b) for(int i=a;i<=b;++i)
10 #define rep0(i,a,b) for(int i=a;i<b;++i)
11 #define eps 1e-8
12 #define int_inf 0x3f3f3f3f
13 #define ll_inf 0x7f7f7f7f7f7f7f7f
14 #define lson (curpos<<1)
15 #define rson (curpos<<1|1)
16 /* namespace */
17 using namespace std;
18 /* header end */
19
20 const int maxn = 2e5 + 10;
21 int n, a, b, k, ans, h[maxn];
22
23 int main() {
24 scanf("%d%d%d%d", &n, &a, &b, &k);
25 for (int i = 0; i < n; i++) {
26 scanf("%d", &h[i]);
27 h[i] %= a + b;
28 if (!h[i]) h[i] = a + b;
29 h[i] = (h[i] - 1) / a;
30 }
31 sort(h, h + n);
32 for (int i = 0; i < n && k >= h[i]; i++) {
33 k -= h[i]; ans++;
34 }
35 printf("%d\n", ans);
36 return 0;
37 }
来源：https://www.cnblogs.com/JHSeng/p/12262172.html