Dashboard - Codeforces Round 918 (Div. 4) - Codeforces
from collections import * def solve(): a, b, c = list(map(int, input().split())) hs = defaultdict(int) hs[a] += 1 hs[b] += 1 hs[c] += 1 for i in hs: if hs[i] == 1: print(i) break T = int(input()) for i in range(T): solve()
package main import ( "bufio" "fmt" "os" ) var in = bufio.NewReader(os.Stdin) func main() { var T int fmt.Fscan(in, &T) for tt := 0; tt < T; tt++ { var a, b, c int fmt.Fscan(in, &a, &b, &c) mp := make(map[int]int) mp[a] += 1 mp[b] += 1 mp[c] += 1 for k, v := range mp { if v == 1 { fmt.Println(k) break } } } }
from collections import * def solve(): g = [] for i in range(3): g.append(input()) x = 0 for i in range(3): for j in range(3): if g[i][j] == '?': x = i st = set(g[x]) for i in range(ord('A'), ord('C') + 1): if chr(i) not in st: print(chr(i)) break T = int(input()) for i in range(T): solve()
package main import ( "bufio" "fmt" "os" "strconv" "strings" ) var in = bufio.NewReader(os.Stdin) func readLine() []string { inp, _ := in.ReadString('\n') return strings.Split(strings.Trim(inp, " \r\n"), " ") } func stoi(s string) int64 { v, _ := strconv.ParseInt(s, 10, 64); return v } func main() { T := stoi(readLine()[0]) for tt := 0; tt < int(T); tt++ { cnt := make([]int, 3) for i := 0; i < 3; i++ { str := readLine()[0] for _, v := range str { if v != '?' { cnt[v-'A']++ } } } for i, v := range cnt { if v == 2 { fmt.Println(string(rune('A' + i))) break } } } }
这道题就是看所给数组的和能不能分解为平方和
import math from collections import * def solve(): n = int(input()) a = list(map(int, input().split())) s = sum(a) ss = int(math.sqrt(s)) if ss * ss == s: print("YES") else: print("NO") T = int(input()) for i in range(T): solve()
package main import ( "bufio" "fmt" "os" "sort" "strconv" "strings" ) var in = bufio.NewReader(os.Stdin) func readLine() []string { ipt, _ := in.ReadString('\n') return strings.Split(strings.Trim(ipt, "\r\n"), " ") } func stoi(s string) int64 { v, _ := strconv.ParseInt(s, 10, 64); return v } func main() { T := int(stoi(readLine()[0])) for tt := 0; tt < T; tt++ { readLine() var s int64 = 0 for _, v := range readLine() { s += stoi(v) } sq := sort.Search(1e9, func(i int) bool { return int64(i)*int64(i) > s }) - 1 if int64(sq)*int64(sq) == s { fmt.Println("YES") } else { fmt.Println("NO") } } }
一个小贪心，当我们遇到辅音字母时，它可以作为开头，就看当前位置往后三个位置是不是辅音字母，如果是，则s[i:i + 3]加到答案中（cvc），否则s[i:i+2] (cv)。
import math from collections import * ll = ['b', 'c', 'd'] def is_c(ss: str) -> bool: return ss in ll def solve(): n = int(input()) s = input() res = [] i = 0 while i < n - 3: if is_c(s[i + 3]): res.append(s[i: i + 3]) res.append('.') i += 3 else: res.append(s[i: i + 2]) res.append('.') i += 2 res.append(s[i:]) print(''.join(res)) T = int(input()) for i in range(T): solve()
package main import ( "bufio" "fmt" "os" "strconv" "strings" ) var in = bufio.NewReader(os.Stdin) func readLine() []string { ipt, _ := in.ReadString('\n') return strings.Split(strings.Trim(ipt, "\r\n"), " ") } func stoi(s string) int64 { v, _ := strconv.ParseInt(s, 10, 64); return v } func Isc(c rune) bool { return c == 'b' || c == 'c' || c == 'd' } func main() { T := int(stoi(readLine()[0])) // 读一个整数 for tt := 0; tt < T; tt++ { n := int(stoi(readLine()[0])) s := readLine()[0] ans := []rune{} ss := []rune(s) i := 0 for i < n-3 { if Isc(rune(s[i+3])) { ans = append(ans, ss[i:i+3]...) ans = append(ans, '.') i += 3 } else { ans = append(ans, ss[i:i+2]...) ans = append(ans, '.') i += 2 } } ans = append(ans, ss[i:]...) fmt.Println(string(ans)) } }
本题就是看有没有一个连续子数组中，奇数和等于偶数和，经典前缀和+哈希
from collections import * from itertools import * def solve(): n = int(input()) a = list(map(int, input().split())) c = set() c.add(0) for i in range(len(a)): if i % 2 == 0: a[i] = -a[i] s = 0 for i in range(n): s += a[i] if s in c: print("YES") return c.add(s) print("NO") T = int(input()) for i in range(T): solve()
package main import ( "bufio" "fmt" "os" "strconv" "strings" ) var in = bufio.NewReader(os.Stdin) func readLine() []string { ipt, _ := in.ReadString('\n') return strings.Split(strings.Trim(ipt, "\r\n"), " ") } func stoi(s string) int64 { v, _ := strconv.ParseInt(s, 10, 64); return v } func Isc(c rune) bool { return c == 'b' || c == 'c' || c == 'd' } func solve() { var n int fmt.Fscan(in, &n) a := make([]int64, n) for i := range a { fmt.Fscan(in, &a[i]) if i%2 == 0 { a[i] = -a[i] } } var s int64 = 0 mp := make(map[int64]bool) mp[0] = true for _, x := range a { s += x if mp[s] { fmt.Println("YES") return } mp[s] = true } fmt.Println("NO") } func main() { var T int fmt.Fscan(in, &T) for tt := 0; tt < T; tt++ { solve() } }
可将问题抽象为一个二维偏序问题，可以使用排序+权值树状数组解决。
由于数据范围太大，要使用离散化减小数据范围
from itertools import * from collections import * import bisect def lowbit(x: int) -> int: return x & -x def update(nums, x, n): while x <= n: nums[x] += 1 x += lowbit(x) def query(nums, x) -> int: res = 0 while x > 0: res += nums[x] x -= lowbit(x) return res def solve(): n = int(input()) se = [] b = [] for _ in range(n): x, y = map(int, input().split()) se.append((x, y)) b.append(y) se.sort(key=lambda x: (x[0], x[1])) b.sort() num = [0] * (n + 1) ans = 0 for i in range(n - 1, -1, -1): idx = bisect.bisect_left(b, se[i][1]) + 1 ans += query(num, idx) update(num, idx, n) print(ans) T = int(input()) for _ in range(T): solve()
package main import ( "bufio" "fmt" "os" "sort" "strconv" "strings" ) var in = bufio.NewReader(os.Stdin) func readLine() []string { ipt, _ := in.ReadString('\n') return strings.Split(strings.Trim(ipt, "\r\n"), " ") } func stoi(s string) int64 { v, _ := strconv.ParseInt(s, 10, 64); return v } func lowbit(x int64) int64 { return x & -x } func add(nums []int64, x int64, n int64) { for x <= n { nums[x] += 1 x += lowbit(x) } } func query(nums []int64, x int64) int64 { var res int64 = 0 for x > 0 { res += nums[x] x -= lowbit(x) } return res } func solve() { var n int fmt.Fscan(in, &n) a := make([][2]int64, n) alls := []int64{} for i := 0; i < n; i++ { fmt.Fscan(in, &a[i][0], &a[i][1]) alls = append(alls, a[i][1]) } sort.Slice(alls, func(i, j int) bool { return alls[i] < alls[j] }) sort.Slice(a, func(i, j int) bool { if a[i][0] == a[j][0] { return a[i][1] < a[j][1] } return a[i][0] < a[j][0] }) num := make([]int64, n+10) var ans int64 for i := n - 1; i >= 0; i-- { idx := int64(sort.Search(len(alls), func(x int) bool { return alls[x] >= a[i][1] })) + 1 ans += query(num, idx) add(num, idx, int64(n)) } fmt.Println(ans) } func main() { var T int fmt.Fscan(in, &T) for tt := 0; tt < T; tt++ { solve() } }