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ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#706472 | #605. Alternating permutation | TheZone | AC ✓ | 15ms | 17768kb | C++20 | 512b | 2024-11-03 11:35:03 | 2024-11-03 11:35:03 |
Judging History
answer
#include<bits/stdc++.h>
#define mod 1000000007
using namespace std;int f[2005][2005];int main(){int n,s,t;scanf("%d%d%d",&n,&s,&t);if(s>t)swap(s,t);f[0][0]=1;for(int i=1;i<=n;++i){if(i==s||i==t){for(int j=0;j<=i;++j){f[i][j+1]=(f[i][j+1]+f[i-1][j])%mod;if(j)f[i][j]=(f[i][j]+f[i-1][j])%mod;
}
}else{
for(int j=0;j<=i;++j){
f[i][j+1]=(f[i][j+1]+1ll*f[i-1][j]*(j+1-(i>s)-(i>t)))%mod;
if(j)f[i][j-1]=(f[i][j-1]+1ll*f[i-1][j]*(j-1))%mod;
}
}
}
printf("%d\n",f[n][1]);
return 0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 4ms
memory: 17764kb
input:
2000 249 662
output:
979748465
result:
ok 1 number(s): "979748465"
Test #2:
score: 0
Accepted
time: 0ms
memory: 4088kb
input:
40 3 36
output:
636639342
result:
ok 1 number(s): "636639342"
Test #3:
score: 0
Accepted
time: 3ms
memory: 10548kb
input:
1080 615 886
output:
725146189
result:
ok 1 number(s): "725146189"
Test #4:
score: 0
Accepted
time: 9ms
memory: 17720kb
input:
2000 1505 232
output:
685039198
result:
ok 1 number(s): "685039198"
Test #5:
score: 0
Accepted
time: 3ms
memory: 17696kb
input:
2000 1727 623
output:
826160131
result:
ok 1 number(s): "826160131"
Test #6:
score: 0
Accepted
time: 14ms
memory: 17632kb
input:
2000 226 391
output:
540336141
result:
ok 1 number(s): "540336141"
Test #7:
score: 0
Accepted
time: 9ms
memory: 17764kb
input:
2000 703 1774
output:
376190159
result:
ok 1 number(s): "376190159"
Test #8:
score: 0
Accepted
time: 10ms
memory: 17636kb
input:
2000 1152 1096
output:
279880243
result:
ok 1 number(s): "279880243"
Test #9:
score: 0
Accepted
time: 13ms
memory: 17548kb
input:
1978 1073 500
output:
507169561
result:
ok 1 number(s): "507169561"
Test #10:
score: 0
Accepted
time: 10ms
memory: 17620kb
input:
2000 1992 1525
output:
738562126
result:
ok 1 number(s): "738562126"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5376kb
input:
332 180 96
output:
981869781
result:
ok 1 number(s): "981869781"
Test #12:
score: 0
Accepted
time: 9ms
memory: 17624kb
input:
2000 509 1085
output:
264447286
result:
ok 1 number(s): "264447286"
Test #13:
score: 0
Accepted
time: 7ms
memory: 17580kb
input:
2000 1278 212
output:
205650795
result:
ok 1 number(s): "205650795"
Test #14:
score: 0
Accepted
time: 11ms
memory: 17576kb
input:
2000 1990 211
output:
968979327
result:
ok 1 number(s): "968979327"
Test #15:
score: 0
Accepted
time: 7ms
memory: 17760kb
input:
2000 1149 1516
output:
33004582
result:
ok 1 number(s): "33004582"
Test #16:
score: 0
Accepted
time: 12ms
memory: 16640kb
input:
1864 410 744
output:
472245768
result:
ok 1 number(s): "472245768"
Test #17:
score: 0
Accepted
time: 0ms
memory: 4016kb
input:
13 1 11
output:
101042
result:
ok 1 number(s): "101042"
Test #18:
score: 0
Accepted
time: 3ms
memory: 17684kb
input:
1998 821 973
output:
290007279
result:
ok 1 number(s): "290007279"
Test #19:
score: 0
Accepted
time: 14ms
memory: 17632kb
input:
2000 23 576
output:
932650726
result:
ok 1 number(s): "932650726"
Test #20:
score: 0
Accepted
time: 6ms
memory: 10492kb
input:
1078 504 314
output:
816976522
result:
ok 1 number(s): "816976522"
Test #21:
score: 0
Accepted
time: 6ms
memory: 16736kb
input:
1874 77 1372
output:
236095030
result:
ok 1 number(s): "236095030"
Test #22:
score: 0
Accepted
time: 7ms
memory: 17628kb
input:
2000 1640 910
output:
186485724
result:
ok 1 number(s): "186485724"
Test #23:
score: 0
Accepted
time: 0ms
memory: 8844kb
input:
883 468 652
output:
90531697
result:
ok 1 number(s): "90531697"
Test #24:
score: 0
Accepted
time: 9ms
memory: 17768kb
input:
2000 344 108
output:
473946379
result:
ok 1 number(s): "473946379"
Test #25:
score: 0
Accepted
time: 6ms
memory: 11316kb
input:
1177 728 957
output:
269338492
result:
ok 1 number(s): "269338492"
Test #26:
score: 0
Accepted
time: 0ms
memory: 7332kb
input:
642 351 495
output:
561170740
result:
ok 1 number(s): "561170740"
Test #27:
score: 0
Accepted
time: 9ms
memory: 17752kb
input:
2000 413 817
output:
897052865
result:
ok 1 number(s): "897052865"
Test #28:
score: 0
Accepted
time: 8ms
memory: 15876kb
input:
1767 69 638
output:
135415850
result:
ok 1 number(s): "135415850"
Test #29:
score: 0
Accepted
time: 9ms
memory: 17624kb
input:
2000 184 591
output:
232066123
result:
ok 1 number(s): "232066123"
Test #30:
score: 0
Accepted
time: 3ms
memory: 17712kb
input:
2000 256 348
output:
169245242
result:
ok 1 number(s): "169245242"
Test #31:
score: 0
Accepted
time: 4ms
memory: 12924kb
input:
1383 1029 240
output:
485589486
result:
ok 1 number(s): "485589486"
Test #32:
score: 0
Accepted
time: 3ms
memory: 7132kb
input:
620 15 70
output:
717885415
result:
ok 1 number(s): "717885415"
Test #33:
score: 0
Accepted
time: 11ms
memory: 17752kb
input:
2000 492 26
output:
981676302
result:
ok 1 number(s): "981676302"
Test #34:
score: 0
Accepted
time: 9ms
memory: 17696kb
input:
2000 1233 1252
output:
301114779
result:
ok 1 number(s): "301114779"
Test #35:
score: 0
Accepted
time: 1ms
memory: 5492kb
input:
353 204 113
output:
888055126
result:
ok 1 number(s): "888055126"
Test #36:
score: 0
Accepted
time: 13ms
memory: 17704kb
input:
2000 1030 311
output:
668443332
result:
ok 1 number(s): "668443332"
Test #37:
score: 0
Accepted
time: 6ms
memory: 17576kb
input:
2000 1038 1399
output:
961335740
result:
ok 1 number(s): "961335740"
Test #38:
score: 0
Accepted
time: 10ms
memory: 17580kb
input:
2000 1823 768
output:
927489489
result:
ok 1 number(s): "927489489"
Test #39:
score: 0
Accepted
time: 9ms
memory: 17632kb
input:
2000 753 858
output:
840245065
result:
ok 1 number(s): "840245065"
Test #40:
score: 0
Accepted
time: 15ms
memory: 17696kb
input:
2000 1996 113
output:
320982302
result:
ok 1 number(s): "320982302"
Test #41:
score: 0
Accepted
time: 4ms
memory: 12728kb
input:
1371 95 520
output:
261577724
result:
ok 1 number(s): "261577724"
Test #42:
score: 0
Accepted
time: 3ms
memory: 12356kb
input:
1317 885 324
output:
923532564
result:
ok 1 number(s): "923532564"
Test #43:
score: 0
Accepted
time: 14ms
memory: 17644kb
input:
2000 1156 1043
output:
47705941
result:
ok 1 number(s): "47705941"
Test #44:
score: 0
Accepted
time: 1ms
memory: 4960kb
input:
238 111 146
output:
611855732
result:
ok 1 number(s): "611855732"
Test #45:
score: 0
Accepted
time: 0ms
memory: 13740kb
input:
1486 281 79
output:
473052686
result:
ok 1 number(s): "473052686"
Test #46:
score: 0
Accepted
time: 11ms
memory: 17680kb
input:
2000 1711 1007
output:
931862496
result:
ok 1 number(s): "931862496"
Test #47:
score: 0
Accepted
time: 7ms
memory: 16708kb
input:
1871 1044 803
output:
479361145
result:
ok 1 number(s): "479361145"
Test #48:
score: 0
Accepted
time: 9ms
memory: 17768kb
input:
2000 1196 825
output:
550086503
result:
ok 1 number(s): "550086503"
Test #49:
score: 0
Accepted
time: 3ms
memory: 13992kb
input:
1526 968 659
output:
360125642
result:
ok 1 number(s): "360125642"
Test #50:
score: 0
Accepted
time: 7ms
memory: 17720kb
input:
2000 1640 616
output:
803535642
result:
ok 1 number(s): "803535642"