回答編集履歴
2
追加
test
CHANGED
@@ -63,3 +63,37 @@
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|
63
63
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}
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64
64
|
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65
65
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```
|
66
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+
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67
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+
関数にしなくても
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68
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+
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69
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+
```
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70
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+
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71
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+
#include <stdio.h>
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72
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+
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73
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+
int main()
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74
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+
|
75
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+
{
|
76
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+
|
77
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+
unsigned u = 0, z;
|
78
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+
|
79
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+
scanf("%u", &u);
|
80
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+
|
81
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+
if ((z = u & 0xffff0000) != 0) u = z;
|
82
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+
|
83
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+
if ((z = u & 0xff00ff00) != 0) u = z;
|
84
|
+
|
85
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+
if ((z = u & 0xf0f0f0f0) != 0) u = z;
|
86
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+
|
87
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+
if ((z = u & 0xcccccccc) != 0) u = z;
|
88
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+
|
89
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+
if ((z = u & 0xaaaaaaaa) != 0) u = z;
|
90
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+
|
91
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+
printf("%u\n", u);
|
92
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+
|
93
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+
return 0;
|
94
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+
|
95
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+
}
|
96
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+
|
97
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+
```
|
98
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+
|
99
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+
でもよかった。
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1
ちょっと変更
test
CHANGED
@@ -2,68 +2,64 @@
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2
2
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3
3
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```
|
4
4
|
|
5
|
-
#include
|
5
|
+
#include <stdio.h>
|
6
6
|
|
7
|
-
int
|
7
|
+
int BitScanReverse(unsigned word)
|
8
8
|
|
9
9
|
{
|
10
10
|
|
11
|
-
|
11
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+
unsigned z;
|
12
12
|
|
13
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-
|
13
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+
int n = 0;
|
14
14
|
|
15
|
-
|
15
|
+
if (word == 0)
|
16
16
|
|
17
|
-
|
17
|
+
return -1;
|
18
18
|
|
19
|
-
|
19
|
+
if ((z = word & 0xffff0000) != 0) {
|
20
20
|
|
21
|
-
|
21
|
+
n += 16; word = z;
|
22
22
|
|
23
|
-
|
23
|
+
}
|
24
24
|
|
25
|
-
|
25
|
+
if ((z = word & 0xff00ff00) != 0) {
|
26
26
|
|
27
|
-
|
27
|
+
n += 8; word = z;
|
28
28
|
|
29
|
-
|
29
|
+
}
|
30
30
|
|
31
|
-
|
31
|
+
if ((z = word & 0xf0f0f0f0) != 0) {
|
32
32
|
|
33
|
-
|
33
|
+
n += 4; word = z;
|
34
34
|
|
35
|
-
|
35
|
+
}
|
36
36
|
|
37
|
-
|
37
|
+
if ((z = word & 0xcccccccc) != 0) {
|
38
38
|
|
39
|
-
|
39
|
+
n += 2; word = z;
|
40
40
|
|
41
|
-
|
41
|
+
}
|
42
42
|
|
43
|
-
}
|
44
|
-
|
45
|
-
|
43
|
+
return (word & 0xaaaaaaaa) ? n + 1 : n;
|
46
44
|
|
47
45
|
}
|
48
46
|
|
49
47
|
|
50
48
|
|
51
|
-
int
|
49
|
+
int main()
|
52
50
|
|
53
51
|
{
|
54
52
|
|
55
|
-
|
53
|
+
unsigned u = 0;
|
56
54
|
|
57
|
-
|
55
|
+
scanf("%u", &u);
|
58
56
|
|
59
|
-
|
57
|
+
int i = BitScanReverse(u);
|
60
58
|
|
61
|
-
|
59
|
+
printf("%u\n", i < 0 ? 0u : (1u << i));
|
62
60
|
|
63
|
-
|
61
|
+
return 0;
|
64
62
|
|
65
63
|
}
|
66
64
|
|
67
|
-
|
68
|
-
|
69
65
|
```
|